Update It has been a month with no contact with the STBXW since introducing her friends my children and her family to her EA PA Co worker.
I drop the girls off where W is staying a half block away. I follow the girls on foot and stay a few houses back, once I we W open the door I duck out without being seen and disappear.
When she drops the girls off, I open the door my youngest comes in right away and I pry my oldest from her moms hands as daughter has clung on to mom and crying. W tries to have small talk I say politely thanks for drop off and into the house I go shutting the door behind me.
Dark as can be with children. E-mails only and I will only reply to questions regarding the girls. Even those questions may be so vague no reply needed.