^ Yes, my atheist grandmother officiates weddings. My agnostic cousin who married us is clergy through the UU church.
My sister-in-law’s dad was a Catholic permanent deacon --he officiated at his daughter’s (my brother’s) wedding. My future d-i-l’s brother will be ordained as a Catholic priest a week before his only sister’s wedding, at which he will officiate. (My son felt a bit weird about this at first, but he is OK with it.) The close relationship that the officiant had/has with the bride made/makes it more personal and special…but maybe a little less balanced or less impartial from the groom’s point of view?
Friend’s kid got married and the FIL officiated. Absolutely wonderful. It was amazingly personal.
My H officiated at friend’s mother’s wedding (re-married after widowhood). Again wonderful.
Knowing the people getting married and adding the extra story or two is really special.
We going to my nephews wedding this weekend. He asked a friend’s father, that he has become close with, to officiate. The man is very excited and got his notary in order to do it - not sure if that’s standard or just so they can cut out a step at some point.