The dissy gas block is designed to work will all of these: MI, Troy, DD.
Self-install should be a non-issue, and the dissy setup isn't much different from what the over-the-block forearms are made for anyway.
MI is going to be the best price, (other than YHM), and their 12" FF 2-Peice rail is probably the best bargain out there for a dissipator type carbine, although the non-FF rails will have a slightly better overall price point and still get the job done.
TROY have slighly different looks, and are slighly more, but again, fantastic quality.
Since they have the sem-uninterruped front (still mount the HWS on the upper only, but it's okay to extend the battery housing over the rails) you'll be super-happy with them.
DD is going to be the outright nicest for the weight (why the cost the most).
If you're looking at just omitting the front sight altogether (and getting a matching front flip-up), I'd seriously look into the MI 10", or the TROY MRF-RX if you want maximum rail coveragle (very unique look on the TROY with the RX, especially on a 16")
As for the light- I'm partial to the vertical grip with the DD offset light mount, although using the Viking one is a tad cheaper and should get the job done great.