Wow, lots of improvement just on this last page! Some really cool stuff here, like how you're going through the full character design process, and your doodles look great too.
I think putting your rendered character designs onto backgrounds is a pointless exercise though - because they were designed from silhouette and to demonstrate detail, they look wooden when placed on a backdrop. Keep them on the plain backgrounds, and when you put them on the backdrop give them more interesting poses.
Just being nitpicky