I like them a lot... my only constructive criticism, and remember I am actively looking for something to say here... I think these looks great.. 

Still maybe the eyes need to be bigger. Unfortunately big eyes make people think of Anime (depending on what you want this could be a bad thing) but pixel art by its very nature is so blocky and low rez that personality and expression can really only be conveyed by text and the eyes. The 1st pic you posted for example.. looks great.. but also has more in common in my brain with a chess piece than a human. I mean it can very well represent a human, but it could also easily represent a chess piece but if the eyes were more prominent, there is no denying what it is.

Example - duck image search

Though it is not a hard and fast rule... I believe that faces trigger some kind of deep natural brain stuff that can make them work or not work in ways you might not expect. We are extremely good at recognizing faces or eyes peering out form the dark at us that even slight "errors" in a face or expression makes our brains go ".. dat weird, bro!.. dat weird.". So if we see a face that looks wrong we go "ok.. that is not a monster trying to eat me, it is a tree stump".. but if we see something that looks like eyes.. we go "ok.. that is a creature out there!!"

So maybe a way to bypass that completely is to make the personalities in the animations and the silhouette.... like the wizard.. has the face obscured completely and the warrior's eyes are just dots. So we see something that looks like a face, but we do not see enough to go.. "ok, that is not actually a face".

So I think that by removing the face completely, you are removing the "facial recognition" part of the brain response or whatever.. and bypassing some of these problems, also if the eyes are big it dosn't matter if it looks like a face, it only needs to look like eyes. ... what I am getting at here I guess is go for BIG eyes.. or NO EYES / DOTS but the real thing to look at is the silhouette shape and make that dynamic in some way.

I have no art skill, nothing I say could be true.. I'm just thinking out loud, so to speak.