Originally Posted by
speedyspaghetti
Its currently indexed Shimano Deore 7 speed, but I was considering switching to 8 or 9 speed microshift with a 1x up front.
There is a good chance your Deore 7 speed rear derailleur will work with 9 speed shifters. Something to think about if it is in really good condition. However, if you are looking at Advent, you'll need a complete system. Also, if you are looking at the really wide range cassettes, you will most likely need a rear derailleur to fit the max cog.
Personally I wouldn't even think about running a 1x8, you should go no less than 9 speed and probably more.
John