Yea MM requires MM-Specific themes.
Good to see it worked out for you man!
The nightlies is up to you man, don't have to install them daily or at all if you don't want to.
From now on though, you won't need to re-install GAPPS unless they update it and you want the latest version. I flash it maybe once a month?
You can do nightlies, stick with stable builds, or only do RC's. Up to you man.