This is a really cute idea and I would totally buy it! I can see that this skin could have an interaction with Maokai or Zyra. I assume the noises it makes would sound less like chimes and more of wind in trees and bird chirping. More like a high 900+ or a legendary skin. It could even be like a sponsor skin where they donate X of the riot points for a nature charity.
The pineapple ult is perfict, it hits the ground and turns into mashed pineapple circles and slices. I think the shell part of the horn idea is better then the blowdart horn as it matches the skin theme of tropical.
I can totally see the meeps being sea creatures like you have or little brown totems like Maokai's tribal skin. The little masks is what I mean, I love the little masks.
Love the skin idea, it's the only one I've seen that's as good if not better then the Santa Bard ideas!