First version from 2015 used to ask, but I have never seen it afterwards, maybe it depends on the version.

No. But make sure to download the correct version.

Yes, MS has copied your hardware info before, if you would be replacing motherboard, that would be more problematic.

If you have activated 10 before, Windows will remember it, there is no need to enter key anymore.
In the future, link your licence to MS account, it will make it easier in case of serious hardware...