Ick. I dislike Papillon a lot. The first thing I think when I see it is papilla, which means "nipple" in Latin. Papilla is also used as a pathological term for any sort of lesion that looks, well, nipple-y. Aside from that association, it looks veyr unfeminine.
Butterfly really isn't much better. It sounds like something a 3 year old would choose for a name. Sorry.