Fair points. For 1, I’d think this would be for use with one person so it would always be “with” them on the floor where they are. But It would be interesting to know if it would disengage to go down or up if needed (though you’d likely need help).

I know the video said she could go up but down down steps, but I’d think she’d need to go up and down on the device.

Fun side story - I once rode a stair chair in my sisters house half way, got bored, got off and walked the rest of the way up the steps to her basement. The stair chair only charged when at either end station (the designers hadn’t planned for it to stop in the middle I guess), so the battery died. It was hundreds of dollars to fix (either new battery or repair tech) and didn’t have a neutral, so it stayed half way up the steps until they got around to taking it out.

1. I think you call an able bodied relative?

2. Looks like it. I think it's just a racheting system, so I think there are infinite "lock points"

No idea if they do it, but I imagine you could pull the whole thing up pretty easily, even easier with some type of winch.