I think you're in trouble with that wall construction.  Those metal studs won't damp much.  Probably the drywall is a better option but you won't have much mounting strength.  It'd be bad for the whole thing to pull off of the wall.

If it were me, I'd try a floor mount and isolation platform(s) under the speakers and equipment.  You don't say how the flooring is installed.  If it's glued down you may be okay.  If it's floating you might need to add a bunch of weight to the stand to push the flooring firmly against the concrete.  

Your various mounting options might just be trading low, mid or high frequency issues.

Whatever you do, do not put something so heavy on a floating floor to prevent it from moving.  That will certainly become your worst nightmare.  secondly a floating floor must have an expansion and contraction gap at the walls and around door jambs.  If it doeasn’t, another nightmare will ensue.

If the above two factors are not given consideration the floating floor will expand and contract with nowhere to got.  Buckling planks will take on whole new meaning.

You can still use a floor stand that is isolated just not overly heavy or you can mount to the dry wall.  There are HD drywall anchors that are now available that are more than suitable and will do a good job.

In my renovation I used steel studs but covered with 5/8” fire block dry wall.  All walls are insulated with Roxul Safe and Sound.  The floor is on concrete and its a floating floor.  But it is a premium grade Cork floor, sadly no longer available.  The planks are cork top layer, cork underlay with a true HDF core.  There is also a 2mm 3 in 1 cushion between the concrete and the floor.  On top there will be a large handknotted Super Agra Rug.

Now will come the room treatment.  

I realize that you will not be able to do all of this.  Perhaps this will give you some guidelines in dealing with your space.

Thanks Joman for the advice.

Actually, that’s not as crazy as it sounds as long as you have spare boards, or can get spare boards.  Individual boards are not that hard to replace especially if the board ends have a “drop & lock” type system.

Cut holes now, small diameter, just large enough to accommodate a spike or cone.  When or if you vacate the space...replace the boards.  In the context of the mind set of audiophiles this would be perfectly rational.

Steve said exactly what I was going to say.

Gotta love it, I'm not alone out there...
Seems like it's going to be...Challenging

Will be looking forward to following this.

Best,
Scott