HI Alanya,
I think I haven't mentioned the SAE site with a lot of John Sayer's tips about studio design....I'm sure John would have directed you there anyway if he answered some of your posts, but here it is anyway:
http://www.saecollege.de/reference_material/index.html
You'll find all the info about floating your rooms in there too, in case you need some more.
As far as the band recordings are concerned, there are a few simple differences between live show recording and studio recording.
I guess they would be:
Live - you have only one take of each song to work with (unless the band hasn't got a big enough repertoir and they repeat some of them

), whereas in the studio you can record multiple takes till you're happy with one. + overdubs etc...
In the studio you would (ideally...*or maybe not..) have instruments well separated (in different rooms/booths) so there's no "leakage" from one instrument to another instrument's mic...
*some bands are recorded in the studios with the whole band in one big room too....
In the studio you can't get that live vibe with the crowd in the background and...you know what I mean...
So yeah there's a few...I'm sure there'll be more comments that you could find helpful...
Good luck...let us know how the project goes...