Have any of you been able to maintain a close friendship with anyone who is still actively a part of your former religion/church?
Friendly, yes. I have few friends and none are, or have been, believers.
Pareto's rule gets applied to everything with me. 20% of the people I know give me 80% of my social headaches in life. I find out what is consistent between those people and remove it from my life. Oddly enough, it isn't religiosity that is the common factor. It's a lack of respect for my autonomy. Sometimes, those people are religious - sometimes not.
I wouldn't say I am super close but I have stayed in touch with 2 people from back in my fundie evangelical days. They are just 2 beautiful people we had kids at the same, so we have a bit of a connection.
Yes, I guess I have, however, the relationships have become much more shallow.