They can be attached on the holes drilled for the rail slots on the sides.
Yes, they will work with your upper receiver.
This handguard cannot accept any external attachments.
As long as your upper receiver is the same dimensions as a standard AR upper, it should work.
No it is not, you will need a hand guard for an "AR10"/"AR308" type rifle. This hand guard is for AR15 platform.
No, it is not.
No, this uses a proprietary mounting pattern.