This Midwest Industries 7.25in Combat Rail T-Series One Piece Free Float Handguard may work on a AR10 but since the manufacturer doesn't mention compatibility with a DPMS AR10 I would consider the other options here.
https://www.opticsplanet.com/handguards-and-forends.html?_iv_gridSize=120&_iv_parent-gun-make=dpms
it will fit. the 7 inch version will be behind the gas block/sight base
no this is the newer combat rail version
No, they would not be compatible.
Yes, it would.
Yes, you could use it with the A2 front sight, but you would need to remove/reinstall after installing the handguard.
You could do that, but it would require removal/reinstall of the A2 sight.
It can be installed on this CMMG firearm, however depending on the barrel length this handguard may be longer than the barrel.