This is not compatible with AR10s.
The Strike Industries Carbine Length Handguard will be compatible with your M&P Sport II. It fits using the delta ring and handguard cap without the need for any modification.
Yes there are heat shields on the inside of the handguards.
Strike Industries does not provide a specific length for this handguard. It is a Carbine length handguard and should fit all AR15's with a carbine gas system that have a delta ring and handguard cap.
No. The Strike Industries Carbine Length Handguard is meant for carbine length rifles and pistols with carbine length gas systems. You have a pistol length barrel/gas system.
Yes it should be compatible.
No, the Sig 556 has a proprietary handguard system.
Yes, it will only work with a delta ring.
It will likely interfere with an Elzetta light mount.