I skimmed over a few of your posts. Seems your SDs are adults, or at least one is. Your DH is not a man to handle his kids and while I'm a huge advocate of disengaging, when they are in YOUR home wreaking havoc, you WILL have to speak up. First, I'd have a meeting with everyone, including DH. "I work and I need help in OUR home. I expect everyone to pitch in and that will mean washing dishes, including other's dishes. A "I'm going to wash my own dishes" will not work. What about the pots to cook in and the dishes to store in? With that mindset, dishwashing will be a chore that will be shared by ALL living in this home." (And any other chores you can think of).

On the first failed attempt, re-address with the same wording and attidtude. After that, in my world, all hell would break loose.

I don't know what your budget is like but if your DH is spineless man type, turn you ask for professional maid services and it comes from his side of the ledger.  In fact get SD to chip in on it too.  But if you do decide to go nuclear (btdt too) it just might be enough for SD to move to grandma's house and that might not be so terrible.  You can just keep reminding  DH it's his fault if that happens, you know, for not parenting and not being a good husband to you.   

"Well, I have stipulated to your dad that we only supportourselves.  So, no food for you, no heat or AC any room you enter, no access to our  property except by express permission any time you approach our property line or any door to your home, and ... buy your own dishes and cooking utensils if you expect to have prepared meals. Anything  you leave out, will be thrown away, nothing  you own can be placed anywhere but in your baggage. If  you need to use something from your baggage, use it and put back in your bag.  You are either a compliant member of this household, or you will not be a member of this household."

If your spouse is such an idiot to have entered into this the SKid only does her own dirty dishes crap agreement with his toxic failed family spawn, find a spouse with half a brain, a spine, and some balls.

smh 

Increase the discomfort for DH and his toxic spawn so the spawn just stops comming to your home.  Abject misery is a great behavioral change method, or even better, runs of the toxic idiots.

Would your husband support charging Rent? Something like $200/month so that you can have a maid come in. 

You have been given sound advice from all the comments above.

Most people do not like confrontation. However you are dealing with an unreasonable person(S) DH and SD. So put your power mindset on and tell both of them that anyone in this house has to make a communal effort. Be firm and calm.

Once you do this you will realize that confrontation is not too hard. If things dont change as others have said make your home so dang uncomfortable for SD.

Here's a thought... 

Don't consider it as "confrontation", consider it more as " clarification of personal responsibilities and expectations for the common good ". It's for everybody's benefit. 

Shes acting like shes a permanent guest. Same thing with my SD16, who hardly does her own dishes and only helps out when asked. If its convenient and she cannot come up with excuses. 

Look, reading through your other posts, Im really glad that you are working with a therapist, and of course writing things out here really does help with validation and strategy. So - re-read your previous posts and the comments and suggestions you have been given. You need to grow a strong backbone. Mini-wife syndrom was mentioned in a previous post.

Yeah. Well because shes in nursing school, she is probably in the "untouchable" classification. And you mentioned shes a b!tch. Shes not just the "kind of person that", she has a chip on her shoulder against you. Like has been mentioned before, you have a husband problem. You two are definitely not on the same page. Bring this up with your therapist. 

Ive told you previously that you need to disengage. Maybe that wasnt something you are ready to do. I would reccomend that you re-read the suggestions here and on other posts, because I really have no additional help to give, as much as I would like to.

I would stop buying the food she likes, put a password on the wifi, change the netflix password, etc.

I would cook a nice dinner for just you and DH.

My SD is 17 graduated high school this year, babysits maybe 6 hours a week and thats it, and is planning on taking a 3 month course to be a dental assistant (2 nights a week for 3 hours). She is so F'ing lazy!!!!

! I went in her room yesterday and her dresser and nightstand was layered in dust! The second she turns 18 (in less than 3 months) I am preparing a cleaning basket for her to keep in her bathroom and telling her she needs to actually clean her room and bathroom. She hasnt washed her sheets for at least 6 months (of course she only sleeps her 8 nights a month but still. I wash our sheets once a week), She has never wiped her bathroom mirror or vanity and has never dusted or vacummed. And her only chore other than making her bed is take her garbage out twice amonth after the weekends she sleeps over. The week before this last time she emptied it but put it in the trash under the kitchensink instead of taking it out to the garbage  can in  the garage. So it filled the kitchen garbarge so I had to take it out. Then this past Monday she forgot and her trash was full of tampons and pads! I was sooo pissed!!!!

Dh wants her to keep coming over as usaul once she turns 18. Lets she how she likes it when I make her actualy do things!!

I'm going to visit my brother next month. Staying for a week. He clearly told me that after three days I'm no longer a guest. Thing is, he didn't even have to tell me that -- on Day 1 I'll be offering to do dishes. Because it's common courtesy.

I've always told kids/steps that it takes everyone living in a household to keep the household functioning. This is one area where my skids step up, and more than my DD too. She sometimes needs The Mom Look, even at 35.

No hints, just straightforward tell SD what you need her to do, and do it with DH present. If there is any negative reaction from the overgrown Princess, DH needs to fix it.

Most nurses I know are caring, empathetic people attracted to the profession because of those traits. I admire the heck out of them. I can't imagine that a nurse with an entitled attitude is going to get very far.