Alright my friend, I don’t consider myself an expert at spriting, but I’ll do my best to give you something to walk home with. I’m going to seperate my critiques by character and any overall comments I have I’ll keep for the end.
#1, The Dissaproving Bandit: I like the facial expression, dunno if that’s custom or not. I think the widow’s peak could be a bit lower, imo he looks a bit too bald at the moment. The outlining is pretty messy all around the face and eyes plus I don’t know why you have random different colors of outlines at the shirt outlines, but it looks very weird and making the outlines one color would solve that. He has potential, but needs a lot of cleaning up.
#2, Probably The Main Lord: It’s hard to tell, but I don’t think he has any eye color, which only makes the pitch black outlines more offputting. Speaking of, I don’t think the pitch black outlines works here, especially if you want him to be consistent with #1. And listen, I used pitch black outlines a lot myself so I know it’s tempting to do, but ultimately it makes the characters look out of place when put next to any vanilla GBA character… There’s also a lot of messy coloring around the edges of the jacket and the shirt inside the jacket. His head placement is a bit awkward, but it could probably work. His color palette is also kinda boring, a bland yellow with a frankly ugly brown. If you made his colors more lively (something that’d pop out to the viewer instead of something that is boring) and cleaned him up, I’d say you’d have something good there.
#3, The Certified Edgy Myrmidon: So I like the black and yellow color scheme, I think that works. On top of that, this one is the most clean out of all the ones you’ve shown here, that and with his strong facial expression, I’d almost wouldn’t believe that it wasn’t vanilla if it was in one of the vanilla GBA games… Almost. There’s some weird splotches of black outline all around the shirt and the grey around the edge of the shirt blends in a little too much with the black; That one is a simple fix, just make the grays a bit lighter so it contrasts better with the rest of the shirt. I also think there could be more yellow on the shirt (so like a bigger yellow design on the shirt) to make the yellow part of the black and yellow palette stand out more. The black looks a bit washed out as well, but I dunno if you could make that any lighter/darker without it blending in or standing out too much with the outline. I like this one a lot, it’s the best out of the three, but it could still use some work.
So, overall I’d recommend you use colors from the vanilla GBA palette, or at least colors that are more lively than what you have now. I understand some people are slaves to vanilla coloring and they don’t get that sometimes the vanilla colors just don’t work, so I can get why you’d want to experiment, but doing so should be looked at as a backup option if you can’t find a vanilla color palette that works with what you’re going for. They all need some cleaning up before you put on a hackbox, to put it bluntly; If the framework is fucked, everything else will be fucked by proxy. But in the end, I think you’ve got a strong start to these and I’m sure with some polishing they’ll look amazing!