Could you provide a picture of your kitchen and island, as they will have the biggest impact style wise. Did you want backs and how many are needed, as size will be a consideration. There are so many directions you could go, even keeping in mind your dining room.

Backless stools

a saddle stool in same color as dining table would be nice compliment. Looks like you have several differing styles in the background, but if you're going in the direction of the dining table houzz has some great saddle stools on their site, whether wood finish, leather etc....

I have no preference as to backs. I would like 3-4 stools. No fabric—because my kids would destroy them. Here’s a pic of the island.

Kid proof, decently priced and I think work with both kitchen and dining set.