[smschulz]

BUIS: Troy's are great even though I haven't used mine yet (have an ACOG)
OPTICS: Have the 512 on another gun and work well ~ not sure if the 522 is brand new or an old item ~ saw that it had an outer Reticle and was actually cheaper than the 512.
RAIL COVERS: I use both Magpul ladder and XT ~ the XT's fit very well.
VFG: Tango Down is as good as the rest. I have one but I put one from SOG Armory that has a rubber outer layer that is very comfortable so I haven't changed yet. I would put the TD on if I had a tac Light with a grip switch though.
PISTOL GRIP: Have the Hogue also have an unused Ergo ~ personally I like the feel and comfort of rubber over plastic.
MAGS: PMag all the way.

Your on the right track!

 

[smschulz]

I live in SW/Sugar Land area. I shoot at American Shooting Center pretty close to you in Katy.

 

[smschulz]

Good choice(s).

One more thing ~ if you are going with (3) Magpul XT covers ~ you might grab one extra.
Since the cover does not cover the full rail you will have some exposed areas. The extra one could be cut to fill in the balance. It is easy to cut and applies well.

I used the ladder for the top but YMMV.