Factory reset...what will automatically save??

I'm having problems connecting during a phone call (won't switch to wifi & other end can't hear me). Project Fi suggested a factory reset. I'm willing to give that a try but I've got my phone set up just the way I want it.

What (if anything) will automatically be saved and reinstalled once the factory reset it done? Will I need to manually reinstall anything (everything!?)? I have backups set up (to my Google acct) and I'll copy all my pics to my computer.

What else should I do? I HATE having to manually redo everything on the phone (it takes SO long) but the phone is worthless if the called party can't hear me (it's fine when I get an incoming call).

Thanks for the help!