Pony Fantasy VI Remake

Hm, okay. Something else I thought of, I was thinking of merging some character roles (Vargas, Dadaluma in Zozo, and Number 128 would all be the same character for story reasons, and the 128 palette swap in Kefka's Tower would be a robot version). So I'm thinking now, if I reuse Vargas's sprite for Dadaluma, that means I can make Dadaluma's sprite something else and reuse it elsewhere, right? In relation, is there an easy way to find out which sprites are used on which maps? Like, "Sprite 17 is on map 1, 5, 6."

Also, I noticed a few sprites (85, 87, 89) are blank. What are they for?