OP, why can't you go to mediation? I think it could be worth a try.
The idea that mediation doesn't work if there is abuse it based on some ideal that does not reflect the reality of family courts. Is it not advised - or is it actually not allowed?
Realistically.... you would need some very robust evidence for him to have no contact whatsoever. On the basis there will be contact, perhaps try mediation just specifically around contact.
In my opinion you need to face this with a huge dose of pragmatism... I'd be thinking, he has every other weekend, he is in their lives (and therefore in yours - but to a lesser extent), how can I make that work as best as possible? Going through a "parenting plan" document could help formalise things. Once formalised the potential for contact conflict/stress could be reduced.
Separate to that identify what the biggest issues are....and what can you do to manage those, what can you not change...?
Eg, do you have tips for keeping the youngest safe? Does older DD have any other adults she can talk to who might be able to help her think things through? Eg favourite teacher. Does she have a plan if she is feeling low at her Dads? Calling a friend to say hi etc.
If your counsellor is still practicing might she be willing to meet you for a one off or one/two sessions that you can make quite focused? It doesn't need to be in depth therapy - could still be useful.