Whether the 7" Strike Industries Strike Rail M-Lok Handguard will cover your gas block or not will depend on what length gas system you have and if you have a low profile gas block. I recommend using the 13.5" Strike Industries Strike Rail M-Lok Handguard to ensure your gas tube and gas block are covered.
Yes, these will work on your rifle.
Yes, the standard Barrel nut should work
No the barrel nut is not included.
No, this handguard is designed specifically for AR-15.
No, this handguard is designed specifically for AR-15.
The Strike Rail is not compatible with the AR10 platform.
The Strike Industries Rail M-Lok Handguard has an internal diameter of 1.57" but will not accommodate most gas piston systems. A low-profile gas block is recommended.
The Strike Rail was designed to fit on Mil-Spec receivers. Looking at pictures of the CMMG Banshee MK17, these rifles have a billet-style receiver. Since billet-style receivers are beefier the anti-rotation tabs may not fit around the upper without modification. As a direct bolt-on, this rail will not be compatible.
The Strike Industries Strike Rail M-Lok Handguard does not include a gas block.