Just a regular flash hider = crush washer
Muzzle brake = something like this: https://www.joeboboutfitters.com/PWS-223-5-56-Muzzle-Device-Alignment-Shim-Set-p/pws-shim.htm
Loctite / Rocksett for when you mount a muzzle device for suppressors...
have you though about building an AR-47 instead ?? Doing a 74 is going to take quite a bit of trial & error to get it to function correctly ! Mostly due to 74 commie rounds have Very hard primers !!
The question you need to ask yourself is what is the role and distance your shooting ?? For me I prefer a full size RDS, easier to acquire a target and most are zeroed at 25 and some at 50 yds.
I got $1837 in parts to just build this 1 rifle... IMO you have A lot of cosmetic (and unnecessary parts) on your list ! For that kind of money you could build to 2 complete rifles. 1 pistol for HD and another for the Mid-range that you seek.