I used to like Mariposa with possible nn Posey. Now for some reason whenever I see it I think of marscarpone (and I didn't know it was used as a derogatory word for gay men before), so that's off-puting.
I still think it's an ok name, but I think I'd actually prefer just using Butterfly in English, as a middle name...or something that's associated with butterflies but not as directly linked (like, you could maybe use
Zinnia because people plant zinnias to attract butterflies).
I also really like
Lila by itself.