Since Morroblivion does not use any assets from Morrowind, can I uninstall Morrowind now that I'm running Morroblivion successfully?
Yea its best to keep it on
Yea its best to keep it on for future versions of the masterfile, otherwise you'll just be reinstalling it over and over again ;)

You'll need it again when the
You'll need it again when the next version is released to install updated master file.