So I wound up discovering the cause of my issue, and it had nothing to do with my ground - rather a plug that I put into the back of the head unit that doesn't go there. Quite honestly this is stupid engineering on behalf of Toyobaru for making a single plug that can go into 2 different locations within a 10" area - but what can ya do?
There is a white plug that goes to the heater/ac controls that can also plug into the back of your head unit. DON'T DO IT:
Apparently there is no connector that goes in the hole with the red arrow above... Or at least none that I could find. After I removed this connector from the head unit I stopped popping fuses left and right.
So you'd think my problems would be over right? I wish. Everything I do on this car is one step forward, two steps back...
Now my door subs aren't working... The brown amp turn on wire has 12V (tested) with the stereo turned on and speakers working, but the front subs aren't playing any bass. The front mids and tweets work just fine. All of my fuses are fine (ALL of them). Someone please help