Sound proofing floor

Adding a 2nd floor should be very effective. Use flexible caulking and then trim to cover the crack between the 2nd floor & the walls. Good luck.

If you have a layout of your equipment and furniture that you will be using it would be a big help in determining placement of minimal support for your added floor.
Don't forget to use T&G ply & glue the joints with something like PL400.
Instead of mass loaded vinyl try to find the heaviest cheapest vinyl flooring on sale(sized to fit room as one piece) and pick up the heaviest "used" foam u/l from a flooring contractor(it normally just goes in the garbage).
Glue the foam to the floor and lay the vinyl over it-gluing the vinyl only to the walls all around to prevent leakage. Relaxed vinyl is vastly more effective.
A layer of vinyl directly on the floor beneath the u/l would be an excellent economical improvement as well.
I will be very interested to follow your endeavour.(I would not recommend lifting your original floor, not worth it, but highly recommend you eliminate any squeaks before you start-and if I were doing it I would rescrew the original floor as a first step using 1&3/4 inch deck screws. Rattles would be very annoying. If the result is not quite adaquate the next step would be to work on the ceiling below. Cheers. Pete

I appreciate your concern Pedrillo & I think it's wise to considerate those eventualities.
I did mention we want the vinyl to be 1 solid piece and also to seal it to the walls(PL 400 will work permanently). I believe the vinyl will slow any outgassing significantly enough that normal routine ventilation will be adaquate. Let's face it most homes are carpeted and the outgassing will move through carpet much easier (faster) than thru vinyl. In addition you will want your plywood floor to be airtight as well-providing a second barrier. So, I think it should be okay. I was not aware of the cotton batting option but I imagine it would be pretty good.

Please inform us of the acoustical engineers advice. It will be interesting to look at the cost benefit ratio. Without going into specifics your idea of a 2nd floor islolated from the 1st is 'very' effective and I think you will find this confirmed by the engineer. (My father is an engineer)

Zargon, thanks for the info on the green glue. I'm doing some renovating and soundproofing for a suite and I'll definitely benefit from your input.