Unfortunately there are no mounting adapters for this sight for pistols at this time due to the proprietary mounting system.
Yes, this should fit most weaver rails.
The sight will bolt on picatinny rails but the sights height is too low to easily see through on an AR
Yes, it would.
Unfortunately, it will not.
No, due to the unique footprint of this optic, they would not be compatible.
Yes, it will come with a hard rubber protective cover included in the box.
Yes, the Nikon Spur will be fine a .30-06.
It will mount to a Benelli Super Black Eagle as long as the shotgun has a picatinny rail mounted to the top of the shotgun.
You will need to use a riser mount for the Nikon Spur as it only comes with a low picatinny style mount. My recommendation would be to measure the height of the red dot from the bottom of the mount to the center of the window. Take that measurement and then subtract it from 1.5". This should give you an ideal riser height to allow you to effectively use it on a Ruger MPR. From there you can use any standard AR back up iron sights like Magpul, Aero Precision or Troy sights with this red dot in that configuration.