How do I remove a rotating display stand and the background on product video

Well, it's the midst of summer. It would be easy enough to find a well lit space outside if it needs to be cheap as F. An old box, a piece of cloth over it, some white linnen as reflectors and diffusors and the grey conmncrete as a background. definitely easier to handle than this mess. otherwise of course you can always do a proper green screen somewhere...

Mylenium

That's a terrible shot. I wouldn't even bother wasting any time on it. This is a case where just reshooting it will save tons of work, time and headache without even needing a second thought.

Mylenium 

You use the same Rotoscopting workflow but need more than one mask. Mocha AE may be better than Rotobrush because there is almost no difference between the foreground and background colors. It is going to require some manual keyframing and adjusting. You are also going to have to deal with the reflections on the top surface of the machine. Mocha Pro would give you better tracking options and an easier way to fix the reflection problem.

If you shot the original footage, I would suggest a reshoot with a better-prepared background and lighting setup. Reshoot, maybe a couple of hours, fixing it in post, probably at least a half a day, but it could take longer.