ANIMATION-CHARACTER DESIGNS

I have an animation short project going on right now-it's probably my biggest animation task to date-to be 4-6 min iin length at finish.
I thought it might be cool to go thru my process step by step in hopes that it helps somebody or compels somebody to tell me what I'm doing wrong-either way I'm open to constructive criticism and advice.

So my 1st step is nailing down the character designs from client's description-
TURTLE-Intelligent , inventor, climbs in and out of shell, uses shell as race car, equips shell with his many inventions.
HARE- self assured blow hard, always running in place, usually dressed in running apparel, dislikes carrots, prefers protein shakes.
LEMMING-not bad just easily persuaded, should look dopey, not very intelligent.

Here's my 1st rough designs...