Battery life maximum is optimized at mid-settings, and as you noted, longevity is dependent on the battery itself, which could run out through ambient decay before that timeframe!
The Strikefire II ships with the cantilever mount only with the low mount available to be purchased as an accessory.
This could be mounted on the 10/22, but these two optics would ride considerably higher than normal. A conventional optic, like our Crossfire-II 1-4x24 in a set of medium-height Hunter rings would be more appropriate, perhaps!
This optic will be configured for a lower-1/3 cowitness, which will incorporate the front sight to a degree, yes! The front will be visible in the lower 1/3 of the window of the optic when running in-tandem!
The Vortex Strikefire II 4 MOA Red Dot Sight will lower 1/3 co-witness with the Magpul Flip Up Sights.
Yes, the Vortex Strikefire II 4 MOA Red Dot Sight can be mounted to an AR15 pattern rifle that uses a fixed front sight gas block. It will provide you with a lower 1/3 co-witness.
These models of the Vortex Strikefire II 4 MOA Red Dot Sight have only a red dot reticle. The Vortex Strikefire II 1x30mm 4MOA Red Dot Sight models at the link below have the option to go between green and red dot reticles.
https://www.opticsplanet.com/vortex-vortex-strikefire-ii-red-dot-4-moa.html
This Vortex Strikefire II 4 MOA Red Dot Sight with Vortex Micro 3x22mm Magnifier comes with a Vortex Strikefire II that has a Red 4 MOA dot reticle. The Vortex Strikefire II that comes in the RG-501 kit has a 4 MOA dot reticle that can be changed from red to green. Both of them would work well on an AR15. The RG-501 kit can be found at the link below.
https://www.opticsplanet.com/v/sf-rg-501-kit2-vortex-strikefire-ii-sight-with.html
The Vortex Strikefire II comes with a standard picatinny/1913 mounting option. It would not be able to directly mount to a A2 carrying handle. You can, however, use a rail mount found in the link below.
https://www.opticsplanet.com/sniper-ar-15-top-mount-picatinny-rail-for-carry-handle.html
According to Vortex it would include CM-304. This can be seen here: VX-RMT-CNTLSTK-1-CM-304