You can try to set a cat thumb for a category and set the bio in the cat description field in the cat editor but from reading your post you like like you want to do something alot grander than that.
The alphabetical member search does not work like you want. If your asking how to hack this in code modifications can be discussed at the hack site
http://www.photopostdev.com
On the support forum we help our customers with normal code problems and questions.