I shorted the sensor wires (FL and RR wheels), tried the ignition on for 30s thing, as well as holding the tire pressure reset button. To no avail.
Nothing shows up in the OBD2 codes, obv.

I thought I'd done my homework, how do I get this stupid light to go off?

 

when you are sure everything is right
and the program doesn't work
something you are sure of
is wrong

a) you did this? to verify the correct reset procedure for the brake sensor warning is to have no feet on the pedals or anything else and turn the key to the 'run' position

DO NOT START

sit this way for 30 seconds (or a bit more)

then turn off

then start and the light should be out - if everything has been connected correctly

b) if this didn't work then the car must be seeing an open on a sensor circuit yet. So either you dislodged a sensor at the connection OR you did not get a good connection when you tied the wires together . . .