ProgZmax, nice paint-over but it's not the style I was heading for. I'm going with no shading (maybe some simple shading eventually) for a cartoon look plus it's easier to animate them that way (hopefully). Plus you got Kronk's outfit color wrong.
What I do need help with is the general pose for each character as well as facial detail especially in the skinnier characters (Kuzco, Yzma, and now Birdwell).
I'm thinking the sprites could maybe be a bit bigger (pasted one to a 320x240 background and stretched it to 1024x768 from there and the character was pretty small across the entire screen) but I tried redrawing Kronk bigger and it came out horrible. I'm really proud of my current version of him. It's Kuzco and Yzma I'm not real proud of.
Anyways, two new ones:
Papi & Birdwell from Kronk's movie:

I also did some slight edits on Kronk.
-Made him slightly taller.
-Squared his shoulders (thanks for idea, ProgZmax)

->

I also gave necks to Kuzco and Yzma:

What needs to be done:
Relax poses and make them have more character. Possibly detail/characterize faces better. Possibly add simple shading.
I still have to draw a few more characters too, and then I'll start the animation process for a walking cycle on each and start up programming. I have a story in mind (unique story that continues off the end of Kronk's New Groove) and a couple puzzle ideas but nothing solid yet.
I'll post about it in the Currently In Production section when I get some background work up.