So, this is an interesting one. For my family, personally, this is our take on it:
I have 20 and 18 yo sons, and a 16 yo daughter. The boys call me Dad, and my daughter calls me Dad or MomD (mom-dee). I fathered them. I am their father. I changed my name on their birth certificates, but my name is listed as the father. It is what it is. They grew up referring to me as Dad. I changed my name and gender, not my parental position. So, for us, we keep that area as it was and they can call me what they will. I know they mean no disrespect toward my gender, and they do use female pronouns when referring to me. My wife mothered them and she has earned that title. It works for us, and sometimes the looks we get in public is kind of comical. Of course, I do not care about being stealth, so for them to outwardly clock me to people in public by calling me Dad does not bother me. To me, it shows people that we are still a tight family and that my transition doesn't 'hurt' my kids (as so many people think).