Yes, you can.
The Vortex VMX-3T Magnifier with Flip Mount will work with the Vortex Razor AMG UH-1 Gen II Holographic Sight.
You could mount this optic to the picatinny rail but it would not be practical due to its size and needing to be paired with a red dot sight.
Yes, the Vortex VMX-3T Magnifier with Flip Mount can be paired with the Vortex AMG UH1.
Yes, this magnifier will work with any of the EOTech red dots.
Vortex support says the diopter range is +3/-3.
Yes, it definitely will.
The Flip Cap Optic Cover size 3 will fit both ends of the magnifier. You will want to set your diopter before installing the flip cap, and once set you should not have to make changes to that. That cover can be found here:
https://www.opticsplanet.com/vortex-rifle-scope-flip-cap-cover.html
Code: VX-R2-VTXCVR-FC-3
MPN: FC-3
UPC: 875874003811
Yes, as long as it's being mounted at the same co-witness level as the Holosun. They may not line up exact, but it will still work.
Every Vortex optic is rated to handle a .308 recoil.