Feeling like you are being held hostage in her closet by your concern for your children is a tough position to be in.  Hope you can make headway.  It is a tough position to be father of children with a mother who is manipulative and what is there you can do - nothing really, but my instinct is to say it is good to focus on looking after yourself, I think it helps your children if you are on the front foot.

I wonder though, if you can't do some sort of a deal with her?  like offer her more money to move out than she would get for custody. but anyway, even though it is a no fault state, I would suggest you document the current situation where it's you who is doing the childcare already, not her.  It will still come down to a judge in a family court.

Sorry to hear about the anxiety, for me it only got better when the stress of separation was over and I had literally moved away from him.  It's like I was a chicken sharing my coop with an egg-gobbling carpet snake.

Lily, 
I did start keeping a log of her activities a few months ago, even went back and filled in as much as I could remember from before. I've been out of town the last 2 nights for work and both nights she's been at a friend's place until midnight, leaving the 17 year old to watch the others all night. 
I think when the youngest turns 12 he'd get to choose who he'd live with, I don't know that I can hold out that long. As is, I may have to cut her off financially just to keep us afloat. 

Rob, I know you'd commented on posts under my old screen name (Started with an N) but I didn't remember you dealing with the witchcraft too. That's probably the biggest issue most people can't really grasp. I get a handful of people saying they hope we can work things out, but regardless of our feelings towards each other, there's a fundamental disconnect in our belief systems now, she has no reason to change, I don't even see how couples counseling would make a difference... it's not a matter of communication, or sharing in chores, to me, it's a heaven and hell issue. 

I'm hoping at least that the state will be reasonable enough to give me residential custody. I work from home, I'm not the one out late every night, I actually grocery shop and cook (she's never cooked more than a microwave dinner and frequently gets ubereats mcdonalds delivery even though it's only a mile away). 

Part of me doesn't want to give up the amount of custody I basically have now, but being able to move on and hopefully have a healthy relationship with someone again would at least give them a better life when they are with me. Then there's the guilt I feel if I do that, that i'm prioritizing myself over them. This continual headtrip is the worst, she's manipulated so much that it trickles into my own ability to reason. 

I'm not 100% sure what else to call it, but her instagram's following tab has tons of "witch" related pages. She's collected a ton of crystals and candles and other ritual items. She's gotten tattoos of a tree of life with mandala roots and some other symbols that are of some sort of cosmic meaning. Her best friend is a self-professed witch, and I know she's been to solstice rituals. Other friends I've been able to find info on also are of the "witchy" type. 
I don't know what specific form it is, but everything I see definitely leans towards witchcraft.