The Spikes lower should work out nicely for your build.
If you leave the upper as it came from BCM, the only tools you'll likely need to acquire is a spanner wrench or AR-15 armorer's tool to tighten the castle nut. I also recommend Brownell's bolt catch pin punch, as it makes it quite simple to install the pin.
I 2nd the recommendation for JP's fire control groups. I've been running a couple of them for years, and have been supremely happy.
The lower parts kit will include both the bolt stop and mag release, and the Spike's kit should work fine. My recent kits were from G&R Tactical and Palmetto State, and they were both of apparently equal quality.......PSA was cheaper.
If you decide on the SOPMOD:
I'm not sure if it was a fluke, but SOPMODs fit so tightly on my BCM buffer tube that sliding from position to position takes considerable effort (yet still wiggles a little once into position). The SOPMOD works well on Vltor's tube, and I happen to appreciate the position number markings. Naturally, LMT's should work very nicely.
I've been considering Magpul's ACS for an upcoming PSA build, but may just get another SOPMOD or E-Mod.
I look forward to your progress.
