I'd go with what you think you can handle, you can work on props for the stages because we need a lot to fill them up.
I can handle the anatomy, texturing, animation, etc. but if you want to make some part of a costume, that's cool.
It should kind of match the rest of the art work though, so if you can match something better go with that.
If you want to do some costume props, you don't have to sculpt it. You can if you want, but even the base mesh would be good to have.
The shin guards for example, I modeled those the classic way in Max.
Every little bit helps