Well, I'm in NY too, and as long as your relatives aren't turning to the court to fix their every complaint, then the court can't really dictate how they co-parent.

If they get along reasonably well, why not let them figure out what works for them in terms of 1 and 2?  As for 3, the court will order how those are to be paid in terms of activities. If they haven't, then I would say that big fees should be split, but small things like field trip fees should be paid out of CS. Your brother will be paying full support until they are 21, since NY doesn't base it on overnights, so he shouldn't have to pay a lot extra, in my opinion.  My DH was only ordered to pay CS and split medical bills.

They have to decide who the parents truly are, either the state or they are .  If they decided they are then they will treat each other with respect and work to stay OUT of court.  Both of them also have to realize that just because they got divorced does not mean their kids get everything they ask for, thereby bankrupting the parents.  No is a still an option with split families.  

If they are resonably sane, the anger should subside in 2 or so years and they will find a somewhat calm rhythm to co-parenting, with healthy boundaries and respect.  Any hint of mental issues on either side and that's where you have problems.  IMO,  that's the way it worked for me and my ex.  DH and BM were another story which led me here 10 years ago.  

Communication with ex: My DH communicated by phone, land line only, and very little with BM, as she was/is high conflict. Now that my SD is an adult (28), he communicates with BM not.at.all.

Drop off/pick up: The only communication that was done in person, was BM yelling about anything and everything. When SD was old enough, DH didn't even walk her to the door.

Extra fees: My SD didn't do any extra curricular activities, my DH did not pay anything to BM above the child support. It worked out for the best, as BM never expected any favors or demanded extra money since he never set that precedent. He nixed that right away because, again, she was very high conflict.

1. COMMUNICATION WITH THE EX- With Meth Mouth is was all via Text, no verbal communication. With my ex is was via letters.

2. Drop off/pick up. DH had sole legal and physical and Meth Mouth had EOW. They did pick up and drop off at a church and there was zero communication. Spawn would just hop from one parents car to the other.

3. As for CS DH paid his full amount to Meth Mouth when she had custody and he also paid for extras like dance, music, etc. When he got custody Meth Mouth contributed nothing and the court ordered she should not. My ex paid a small amount of CS each month and that was all. DH and I raised the children with our own money and provided everything their useless donors never did.

Let me stress that things change as time goes on....good or bad....they do change.

I am going to answer your questions based on TODAY.....when I first starting posting here things were very different...and before that even more different. In my case.....4 years in...things are 100% better.

1. DH rarely texts or calls BM...he mostly texts the kids (12 & 17) directly regarding schedules. If BM texts or calls him...it is also rare but is to the point and nothing else. I'd say on average they have 2 text conversations a month....that is it There is no reason to communicate unless there is a schedule change, a sick kid, or something major at school.....

2. Absolutely 100 percent NO. They are dropped off out front and go in on their own. There is NOTHING to discuss, period. I would say on average...DH and BM speak in person maybe 3 times a year if they happen to be at a school conference or function.

3. YES. he splits everything....doesn't matter what it is or how much it costs. If BM asks for it, she gets it.

3. Split? NO...thank god. If the kids happen to be at our house and need money or something else for an activity or sport......they get it..but not in excess since...CS!!!! . If BM texts DH asking for half of payment for something.........NO NO NO.

Now, just for FUN....let me now answer these same questions based on my life when DH and I first got together....the below lasted 6 months-ish.

1. DH is at the beck and call of BM. If his phone rings he panics and answers immediately......he talks as long as she wants and lets her yell at him. He would never dream of not answering or ignorning a text. There are daily conversations....if I'm talking to DH and BM calls.....I get shoved aside so he can run to the phone. Every issue is discussed.....and he says yes and please and thank you to anything she says.

2. Yes, he walks them to the door and discusses anything. He will even attend birthday parties and "babysit" the kids in BM's home. When she drops off the kids to him....she will also come in for a visit. DH will ask permission before he does anything for or with kids.......

Unfortunatly for me I think I waited to long before I tried to push back against BM's crap and DH would not see it my way.

This is key, to let your boundaries be known before you've put up with the crap so long, it's too late for change. They just expect you to accept it forever.

We are hesitant in the beginning stages of a relationship to put up those boundaries, lest it look like we are trying to tell them what to do and how to handle their business, when we've just come onto the scene, but it's important. They don't have to change the way they do things or respect our boundaries, but then we know where we stand and can leave before too much time is invested.

I never told my DH, "This is how you will handle BM." I simply made a statement (and put it in action) about what I would NOT put up with. Take it or leave it.

I'll caveat this by saying my DH and BM are pretty cooperative and cordial, so what works for them might not work for your brother.

COMMUNICATION WITH THE EX- Most communication is by text.  It's mostly about logistics and requested schedule changes, occasionally for a skid issue.  Maybe once a week on average.

2. Drop off/pick up. Most of our exchanges are at the school bus stop in front of our house - kids get off the bus and into BM's car - so very little communication regarding the skids is done in person.  They might discuss something if we're all at a school event, but since DH is usually at work during exchanges, they rarely see each other.

3. DH doesn't pay child support (50/50).  BM pays for activities she signs the kids up for, and DH pays for what he signs them up for.  Before BM remarried (to a guy with a healthy 6 figure income), DH would pay the school fees, buy school supplies, pay for field trips, etc., but now they both buy supplies and whoever has the kid when the field trip form comes home usually pays the fee.  So far there haven't been any big expenses and they don't nickel and dime each other over the small ones.

Edited to add:  DH and BM communicated much more, saw each other more often and did some joint activities/parties before I was in the picture.  Part of the change is that the skids got older and went to school (they were 1 and 4 when DH and BM divorced, 4 and 7 now), and part of the change is that I insisted on boundaries.

1. Bm here is crazy so there is zero contact between her and dh. Dh immediately got sd9 (at the time she was 7) a cell phone so they could communicate any schedule variances through the child. However, they have always had a set schedule so everyone knows when pick up and drop offs are to occur. 
 

2. Pick up and drop offs occur at dh parents home and dh doesn't leave to pick the child up until the child confirms she is there in case bm is late. Dh doesn't want to see bm at all. 
 

3. Dh doesn't pay child support but does provide healthcare to the child and would pay for activities if she were in any since the bm wouldn't. He buys her items for our home including clothes but doesn't allow her to take anything from our home to bm home except her cell phone. 

Dh carefully crafted this so he doesn't have to interact at all with bm. On the rare occasions she has text him for something she is verbally abusive to him so he doesn't respond. 

My DW did not communicate with the SpermIdiot.  He was almost completely uninvolved with anything to do with SS.  SpermGrandHag was the interface point with my DW for the SpermClan.

1. Communication was either by telephone or via our lawyer's letter head. Communication was only for arranging visitation travel to facilitate travel to and from SpermLand.  No communication about school or medical issues with the exception of notifying them that he had broken his arm (when he was 4) which initiated an explosion from SpermGrandHag that we had gotten him a bright red caste to ruin the SpermIdiot's sister's wedding (he was 4 and he picked the color), and to notify them that he would be attending Military boarding school for HS.  SpermGrandHag went ballistic over that ranting that we were trying to kill him by forcing him into the military and that she would not pay a penny of the costs.  SpermIdiot never paid a penny of anything. Not even the CS. SPermGrandHag and SpermGrandPa paid all of the CS for my SS for 17+ years and paid for the SpermIdiot's half of visitation travel costs.

2. The SpermIdiot never traveled to pick up or drop off SS.  The SpermClan sent SS's GGF to pick him up, or they had SS's aunt's MIL come to pick him up. Her daughter lived in the same city we were living in.  The SpermGrandHag would pay for her flight to pick SS up.  DW laid eyes on the SpermIdiot only twice in the 16+ years of the CO (other than in court).  That was in a parking lot where they transferred SS when my wife was in SpermLand visiting her family.  There was probably only a couple of dozen words spoken.  SpermIdiot would call once every five years or so to tearfully profess his love for my DW and cry that he wanted his family back. She would laugh and ask him if he wanted to speak with his son.  

3. My DW was the CP.  The CO awarded a pittance in CS.  Initially $110/mo for a year. Then $133/mo for 9 years.  Then settled at $385/mo for the last 7 years of the CO.  Even as the SO of the CP, I understand that NCPs tend to get rapped for ridiculous amounts of CS.  CS is all that an NCP is obligated to pay in support of their prior relationship children if there are not other support elements stipulated in the CO.  In addition to CS the SpermIdiot was obligated to provide medical insurance coverage for SS (which the SpermIdiot never provided), and pay half of any medical related costs not covered by insurance.  The SpermClan never payed a penny of what they owed my DW for uncovered medical expenses.  With penalties and interest (from the IRS penalties and interest tables) they owe my CW more than $10K.  She sends them a statement twice a year with fresh penalties and interest applied to keep her claim on that debt active so if necessary she can smack them with a law suit if they don't stay under their slime covered rock and leave SS alone. Since SS-27 launched they have periodically attempted to guilt him into sending money to support his three younger also out of wedlock SpermIdiot spawned half sibs by two other baby mamas. CS is it.   Unless otherwise stipulated in the CO.

If the NCP wants to provide more for their kid, I would suggest that it be provided directly to the kid and not to the X.  

So, no communication with the X other than what is absolutely necessary in addressing specific kid related issues and only what is critically important.  No money other than CS ordered in a CO (or other COd support elements), and no face to face interface other than kid hand off or in court.  

Unless... both Xs are reasonable and can interface reasonably.

All IMHO.