None of us know any of the players in this sad mess, but I think most of us here agree that Ioan comes across as a sensitive and kind man and a loving father. Being rejected by his own children must be unbearably hurtful. I believe he hasn't forced contact the past few months because he wants and needs for them to want to see him, if that makes any sense. He has been a victim of coercive control himself and doesn't want to do exactly that to his kids.
In my view, Ella is lost to him and he should let her go in the hope that she comes around like the proverbial bird that's been set free. She has shown with various behaviors that she takes after her mother, who has groomed her well. The same sense of entitlement, lack of boundaries. Throwing a fit when at her dad's apartment, most likely because he tried to establish rules about screen time, chores or something of the sort. Expecting that he drops everything to drive her to school after shutting him out for months. Equating being pulled out of an elite school he couldn't afford with child abuse. Hacking his Insta.
Elsie I really feel sorry for. I think she is in a very bad place, being manipulated and bullied by her mother and her big sister. What is an 8-year-old going to do when Mommie Dearest and Big Sis say, no, dad is a cad and you're not talking to him. A kid that age doesn't have that much strength of freewill.
Once the PRO is in place and he has increased leverage in custody, Ioan needs to fight for Elsie. I know, I know, it's frowned upon to separate siblings, but in this case I think it would be the best for everyone. They are 4 years apart, that age gap is going to become more significant as Ella moves into adolescence and Elsie is still in Barbie and unicorn mode. Ella has more of a bond with her mother, Elsie more with her father. Ioan could get Elsie the therapy she needs to get through all of this. And I can totally see Bianca being an understanding and cool stepmom to an 8-year-old. That would be my hoped for outcome.