Sudden loss of pedal

First off I greatly appreciate all the responses! To answer a couple questions.

The system was working perfectly fine prior to me doing this brake work. Id be surprised if the MC suddenly failed, but I've seen crazier to be fair

I did not back off the E-brake adjustment. I honestly did not even realize that was something to do prior to adjusting shoes. I've always adjusted shoes, then adjusted the E-brake.

I believe TrailBeast hit it on the head though that the logical first step is bleeding. However, I figure if I got to bleed, might as well give her new wheel cylinders while I am at it.