Yes, it will come with both the set screws and gas tube roll pin.
Yes, it will as long as your barrel uses a .750 diameter gas block. You need to verify the gas block diameter for your specific barrel.
Yes, the AIM Sports Inc .750 Mil-Spec Low Profile Gas Block is compatible with the Ruger AR556, as well as any AR15 that uses a 0.750" gas journal.
As long as the barrel diameter is .750, it should work.
Yes, as long as your gas block journal is .750.
Blue Loctite will be enough. If you are worried about any issues especially if you will be shooting a lot you could use red if you are worried about heat, but it will be difficult to remove.
This is a mil-spec gas block with the hole drilled all the way through. This in no way impedes the operation of your AR.
Yes, this will work with your M&P Sport II.
Yes, as long as the barrel has a .750" gas journal.
Yes, this will work on an M&P Sport II.