Yes you can. This solar camera has a built-in battery of 10000 mAh that is 100% wireless. No need to use a power cord, you can use it anywhere. 

No, you need to install the magnetic adapter first; 

No. I bought it based on the claim that it would support the weight, but it doesn't. However, i have found that if I don't try to use the cantilevered function, but just use the height of the combined tripod and arm (straight up) and the ball joint holding the binoculars, I have more than enough height to see anything up to about 75 degrees comfortably. In the video, the eyepieces are at 6', and there is easily another foot of extension available. 

Yes, it will fit any Sony e mount body, either full frame (a7..., a9...), or aps-c (like a6500, etc) 

yes, i had no problems with infinity focus with this adapter. the only FD mount lens i use anymore with my sony is a vivitar 20mm, and i pretty much only shoot infinity focus with it.