Grounding Metal Outlet Boxes and Isolated Ground Receptacles

Always follow code first. The use of plastic boxes are not legal in many areas. Nor is armored cable and romex 
Given what you posted I’m assuming 1900 4 by 4 deep boxes were used and emt is the conduit. Running a separate ground is pointless. The screws and or outlet mount fins is what grounds it. The reason there is a seperate ground screw on the outlet is because there has to be. Grounding screw on all outlets. It’s there for when metal is not used as the transmission. I.e... using a plastic box

#6 is overkill. Amplifiers draw between 2 and 4 amps max

depending on what your running I would have ran two dedicated 20 amp on min #10 wire on a shared neutral.

the outlets you bought are good but so is just about any hospital grade. I’d be surprised if a furutech accepts #6 wire.

verify the panel is grounded correct. Tap after your main water shut off and jump to before the shut off valve

cheers

Addressed well Jim ;)

i am in Chicago, very strict here on what can and can't be acccepted. 

Manditory with the conjunction of any gfci outlet. Your talking in newer builds money adding each of those to a panel. All must have dedicated neutral and cannot be shared. I've seen debate there but it's my understanding the faults won't work correctly unless dedicated. 

any remodel on older work must also incoperate same or your grandfathered in.

all interior raceways must be emt or rigid. Why run rigid when yiu can use emt. 

You can can whip up to 5 feet only for lighting. Some inspectors will require a ground with that use. 

As as far as I know all exterior work must be rigid only. 

also depends on the inspector and what that one thing they look for... you know how it is. 

Chicago is lunicy and just plain overkill. 

I was asked by my local inspector or should I say forced to add Afci to all my gfci dedicated runs.  Nevermind bedrooms/living areas as they are normally intended for where homes do not have smoke carbon detects ran in series..  

you asked if it was maditory. It was for me but would depend on the inspector from what I've seen.  What cannot be ignored unfortunately is basically the amount of labor required to complete jobs satisfactory. 

Cheers ;)