I don't think Luke & Leia's relationship went beyond "the kiss" at all...Han & Leia barely had time for a relationship, so I doubt Luke & Leia would have either.
I think Luke is a totally cool name to have ToMac.....I mean the SW reference is hard to get away from, but I want to name our next labrador Luke. Now, don't take offense, I don't have any kids.....but they're great dogs !!!!!!