You need to pick your battles.

What is most important to you? That the skids help clean up? That they interact with you? That you know the schedule? That DH clear things with you in private before giving the okay to the skids?

In his mind he's doing things for his Children, not for BM. The why and whatnot doesn't matter, if BM gets a night off because of it, oh well that's nothing to him. He's spending time with his kids.

DH is very much like this and BM took total advantage of him. It made me crazy. I had to give him boundries and let him know what was important to me. I also had to let go of a lot of the stuff that BM did and still does. She is going to do what she does no matter what you do. Sometimes she'll do things just to spite you.

Learn to let it go, or come here to vent and complain but don't keep bringing it up with DH unless it crosses a line.

Now BM driving by your house is one of the things I'd say something about. I would make a big deal out of it but I'd mention that it sounds like her life is a country song and wonder why she's resorting to driving by your house. Say it to DH, not to the skids. Never say anything bad about BM in front of the skids. She's their mother and they will be protective of her. They won't see her crazy, they will see a mom who's concerned about her children and a Stepmother who's overbearing and controlling.

All the other details about SD, SS, and SS aside, regards the basic expectations of respect in your own home - that is and should be a non-issue. You are an equity life partner, and deserve to be respected in your own home. They are older, and therefore getting them accustomed to a "new order" will be a matter of repetition. Its taken me 4 years, and still have to remind SD12 I need help. 

As to the other thing, that is very important to address! Establishing boundaries as soon as you can with the BM between her and your DH, is very dificult, because she is accostomed to getting her way every time without respecting others. I know this because I have also been in this situation for 4 years. Firstly, I came into things very naivly. BM and SO had just split up and were separated but not yet divorced. So we had to "keep her happy" so divorce would be easier (it wasnt). Then it was her demanding things that were promised her, like a mirror that was hanging over the fireplace mantle that I had really grown to love over 3 plus years. I said "get that thing over there, but DO NOT UNDER ANY CIRCUMSTANCES hang it for her, because she will ask you". (she did, he said get one of your studs to do it....") Then she asked to borrow his truck, to haul furniture (back in March, when tax return monies came in), then can he please come over to her apartment to measure for new furniture that was being considered for purchase.

I finally, after 4 years of this, went ballistic. Dude, you divorced this woman, you are no longer her "honey do" - er!!!!!!! I told him this:

"Tell her no when she asks, and do not give a reason" He would make up silly reasons and excuses. Drove me nuts.

So, he calls her and tells her "No, CLove doesnt want me to...shes not comfortable with it". 

Her response was "fine" click.

Yes, I know that it was him throwing me under the bus a little, but it was the truth, the truth he needed to tell, to keep things nice for Munchkin. Im ok with that, because now the boundaries are CRYSTAL CLEAR, no question about them. 

So I would advise that you communicate with your DH, what boundaries he must create and enforce with BM. Do it now, or you will be upset for a very loooooong time.

If it affects you, you have a right to know and have input...and most of what happens between a married couple will affect you. I'm glad to hear your DH is working on bringing you into the loop more frequently. That was my biggest pet peeve early in our marriage (aka the last to know phenomenon). 

It sounds like you have a lot of trigger points right now, so you can't pinpoint what bothers you the most or why. You're drowning in the chaos. In this situation, I recommend you disengage completely...so you can evaluate your feelings...and then reengage where you feel able to do so. This is kind of what I did. I quit doing or being there for the skids for a bit so I could get a handle on what I wanted and who I wanted to be...then I realized how and when I could be involved. 

So...it's not your night to have skids and your DH allows them to come over without talking to you first? That's fine...unfortunately, you had plans to go run some errands.  If he'd talked to you about it, you could have rescheduled. Then you head out the door and let him figure out dinner, entertainment, clean up, etc. What you don't do is JUMP every time DH rearranges the schedule on you. Your plans are set...if his aren't, that's not your problem to fix. It's his. 

Make sense? 

Yeah. And no way in heck would food that I cooked be heading over to BM's house unless it was MY idea (having said that...I have sent leftovers with the skids before, simply because it was a favorite meal of theirs and there was more than DH and I would eat on our own. Not EVER because BM demanded it of me. Please...the nerve.) 

Hope this helps. Everything your DH is doing sounds totally unreasonable to me...but he's probably drowning in the chaos, too. The only way to fix it is to determine what you need and be firm. To be able to do so, you may need to take a few big steps back for a couple months...your doing so will likely help DH find his boundaries, too...once you're not picking up his slack. 

I don't think I would mind if we had had one of the SD's to dinner and her sister asked her to bring her some leftovers.  like.. oooh.. bring me a piece of ESMOD's meatloaf and crispy potatoes... I love them.  I would personally pack up a togo container for the kid.  But if BM had demanded we send food home with the stepkid?  uh.. nope.  Lady I am not responsible for sending food to your house that in all likelihood would be eaten by you and your BF. 

These kids are teens.. If one of the teens called a teen at your house and asked for leftovers.. fine.  But not at BM's request.. that is overstepping.  If he seriously thinks BM isn't buying the kids food he can give his child some money to stop by the grocery store to buy bread and cold cuts like my DH used to do for his girls.. take them shopping for groceries because MOTYBM couldn't be bothered to grocery shop.

I mean, it's not like you had an issue with them eating over on a non-visitation day.. and I personally think that's ok as long as meals are casual enough to allow for that.  I do think you had a right to stop the Skid from calling mom until the table was cleared though.