I'm thinking of downloading Morrowind Overhaul because it looks really good and much easier than individually downloading a whole bunch of mods. But will Morrowind Comes Alive work with this mod? Also, this might be a really dumb question, but does this mod also work with Tamriel Rebuilt? Thanks.

Yup it works with MCA, I had it running with MCA and Starfire's NPCs additions together and it runs fine. I have not installed Tamriel Rebuilt so I'm not so sure of its compatibility, but I read somewhere that it works well with Morrowind Overhaul.

Absolutely. Both MCA and TR work fine with Morrowind Overhaul

Do you think I should install Morrowind Overhaul before or after MCA/TR?

Before sounds better, but you can install it after too I suppose. ^^