I see the 4th boss's gloves and shoes, but not his hat and bow tie. I know they're in different a part of the PPU, but still.

If I'm not mistaken, this sheet also includes the bosses. Nicely ripped, very thorough, near as I can tell(though obviously a few of the things, like the flashing red jewel, require the background tiles to get the sense of how they look in game. It's a crocodile statue with the jewel on the forehead).

How sure are we of the pallet for the unused enemies? I don't recall this game doing pallet swaps so they're probably pretty accurate(unless there's data that implies pallet swaps that I don't know about), but I've sometimes found that the unused graphics, while always appreciated because they're interesting, are sometimes guesswork as to how they were intended to look.