I think you may run into problems running an H2 and weaker ammo with an LMT upper. Stick to 5.56 and you should be fine, cheaper .223 might not give you enough gas to cycle reliably.
yankee hill handguards are not well respected… i’d invest another $50 and upgrade that part to a DD or larue, or even just a RAS if you can find the $150 deals i see on kits here and there
I agree. With the money you are already putting into your rifle, get a rail that is equal in terms of quality. I run Daniel Defense Lite rails on my rifles and love em. I don’t own any others so I cannot comment. I did however have a YHM rail and it was a long way from my DD in terms of quality. Hope this helps. Everything else sounds great and please post some pictures when you get everything assembled.
I really like my Troy MRF-M on my BCM middy, took me 5 minutes to put on biggest thing was getting the snap ring off (grinder with a cut off wheel) $179 shipped