[Doublehelix]

Your ceilings are going to be too low, and will not pass inspection. They are out of compliance, and could cause you problems. If you do not do an inspection, the entire area will not be covered by your homeowner's insurance, and would represent a total loss due to fire, flood, tornado, etc. Plus, if someone gets injured down there, you will lose your shirt.

You are going to get lots of noise into the above floor if the wall studs are attached to the floor joists above. The sound will travel by flanking, and you will get lots of sound transmission... more than you would guess actually! If you can, make the walls free-standing so that they do not touch the ceiling joists. If not, then understand your limitations, and be prepared for lots of noise transfer.

Staggered stud walls are "ok", but from what I have heard (read) they are not much better than single stud walls, and are a lot more work and cost. I have no personal experience here, but this is what I was told when I did my build-out. I went with isolated double walls, and a room-within-a-room design.

Also, what are you thinking about HVAC? This is a huge issue, including fresh air returns, both to meet spec, and to provide comfort and fresh air to the talent. It will become very uncomfortable without it! Folks get cranky without oxygen! If you are planning in tying into your existing house HVAC system, sound will travel through there as well. You can build silencers into your basement ductwork, but these are not 100% effective, and are difficult to build.

The best way to stop sound transmission is mass, mass, and more mass!!! The fluffy insulation will help a bit, but you might want to consider putting drywall between the floor joists, attached to the upstairs ceiling, sealing around the edges with acoustic caulk. Several layers will be required to really help stop sound transmission (in addition to insulation). BE CAREFUL HERE HOWEVER!!! I cannot stress this enough! Your structure might not be able to handle the additional weight of the drywall (it is heavy stuff), and your whole house could come tumbling down!!! You can get a structural engineer out to check this out for your about US$100 or so, and he/she can tell you if your existing structure can withstand the additional weight. It is money WELL-SPENT!!!

Good luck! Remember, a good plan will save a lot of headaches later on.