Monoprice Product 39306

1 - Yes it has two separate vertical bars, so you will be good to go

2 - Yes, you can slide it left or right, but depending on the width of the screen and the distance off center of the studs, you may see the bracket.

3 - As previously stated, you will probably see a gap, and the lowering/raising handle

4 - Dont know, but the types I have worked with usually take some effort, as they use friction to hold the positions, but let us know.

Use the longest screws you need. Just make sure they aren't too long, although I think most manufacturers have made them with stops at the bottoms, I have cracked a screen by using too long a screw. And make sure to use spacers between the mount and screen, usually they are provided with the mount, if not, a bunch of washers will work, to get a good grip.

Add a washer on both sides of the keyhole and tighten it down, should hold it no problem.

Your options are very limited, as you seem to know. You can try the following mount, and mount it on the ceiling or bracketing it to the wall, and use it in the reverse direction. Otherwise, you can purchase or make a thin cabinet to place against the wall that will house the tv until you are ready to use it. Have never tried it myself, so I can't say if it will work or not. Someone in the question section asked it and the answer was a resounding maybe.

https://www.amazon.com/gp/aw/d/B075PMXX4F/ref=sspa_mw_detail_6?ie=UTF8&psc=1

Theres also these if you have some extra cash on hand, takes care of the tv being on top of anything:

https://www.tvliftcabinet.com/tv-lifts?cabinets_tvlift_tvsize=322