1. No it isn’t normal (unless you happen to have a very slow internet connection), it sounds like it has stalled.
  2. My guess would be a failed installation, probably resulting in a corrupt installation.
  3. Unless other updates occurred that also required an reboot, if they don’t immediately restart then when all are done a reboot should cover all.
  4. Personally I wouldn’t close it, but I don’t know if there would be any ramification.
  5. I don’t know, but I wouldn’t suggest doing it.
  6. I guess this would be no different to 3. above.

There is a hell of a lot of speculation in here I rather doubt all of this could happen together/coincidentally.
So have any of these actually happened ?

That’s me for the night 2:10am here.