Changing which characters have eye sprites in Super Mario Bros. 2

[Midna]

I'm doing a sprite swap hack of Super Mario Bros. 2 (the NES one), and I've run into two small problems:

1. The character I'm replacing Peach with has the same white-orange-dark blue color scheme that Toad has in an unmodified game. This means I don't have to use additional sprites to make the new character's eyes white, since I can just use the white color that's already in their palette. The problem here is that Peach's eye sprites are still loaded for the new character, which is unnecessary.
2. Toad doesn't load eye sprites at all, which ordinarily isn't a huge deal because his eyes are black dots anyway. The character I'm replacing Toad with, though, does have white eyes, so if I don't make any changes, they'll end up with what TV Tropes has dubbed "skintone sclerae."

So, what I'm wondering is: Is there any way to change which characters use the "eye sprites"? Specifically, to transfer Peach's over to Toad's?

[henke37]

They way to change it is to change the code responsible for the character animations. Good luck! If the luck is with you, there will be an annotated disassembly of the game.

[Midna]

I guess luck isn't with me, then. There's a Super Mario Bros. 2 disassembly, but it's for the game we call The Lost Levels. For a game that had such influence on the series, it sure seems like not a lot of people are interested in learning to make it tick.

Skintone sclerae it is, then...?