Sweet heat is a nice flavor. I have sweet heat pickles I put on a lot of things. But Skittles are synonymous with fruit so I don't know if I would try them. I'd still be expecting a fruity flavor, not spicy.

The Mentos I can definitely see. I've always liked how Mentos have a good chew to them.

Doritos, I don't know. I sometimes dip my regular chips in ketchup, but I don't know if a corn chip like Doritos would be the same.