blend tree setup for arbitrary scalar properties in mecanim?

Hey guys I am a noob to animation so I need some HELPZ PLZ,

I like mecanim but I am trying to rig up a hamster (quadruped) that crawls around through tubes. It would be nice to make a blend tree with three states (IDLE, WALK and RUN) for it that animates based off an arbitrary number of scalar parameters like these: walkspeed -> IDLE/WALK/RUN body bend -> left/right body arched -> up/down body twisted -> clockwise/counterclockwise body spread -> in/out mood -> happy/glum

Is there any way in mecanim to throw something together form clips like these, walk, walk bent, walk twisted, walk arched, walk spread, walk happy, walk glum,

Do I just use nested 2D blending? Is there anyway I can just get a normalized blend tree from 5 or 6 parameters or do I need to use may states and make walk happy bent, walk happy arched, walk happy twisted walk happy spread

Also when do I use animation layers vs. animation states vs. blend trees? The three things mecanim seems to have a lot of.

So may questions, so little hours in the day. Help me unityAnswers. Help me.

Also if you want to help me more you can PM me. I am almost ready to start a collaboration on this game. I have hamsters that navigate through pipes, and cages, that you can buy at a store thingy, and build in a room. I just need this animation working so they don't jitter everywhere. I will edit this when I put up a post on the collaboration forums. PM me if you want to help.