Dell publishes the specs, just look them up at Dell.com/support. Punch in your service tag and it'll tell you everything you need to know. Well, mostly.

You'll need to lookup the Dell part number for the PSU to find its specific capabilities (number of 12v buses for example). Looks like it came with a 365w unit, so you may get lucky.

I don't see moving the board as being realistic. You can't really do that in any case-they're all designed to mount a certain way, and branded boxes are even tighter. But that PC is a mini tower, so there's little reason why you wouldn't be able to put in whatever you want - more drives, etc.

You should be able to find drive cradles on ebay. Or just mount them however you can. I've gone as far as gluing a drive to the case with Goop (a rubbery adhesive). Cradles just make it easy and consistent.