Oh gees, sorry to hear that, looked like a great pup! Bet you have lots of great memories you'll be sure to hold on to. I think it's tougher losing a critter then a person, lost my mini schnauzer in Nov., it still gets to me .
I'd say your mc is maybe an MBM unit, outlets out both sides, but pick a side, plug the other two. If you are using disc up front, drums on the back, you use a 2lb residual for the front, and a 10lb. on the back, as disc need less kept pressure due to their built in design in keeping the piston...
A bit more done, lake pipes, steering, inching there. As this is a winter project it's coming to an end, but trying to get it to start, steer, and stop, all I have left of that list is the master/brake pedal.
I went back and checked out that post on your build, and saw your mc location before I posted . ALL masters c's that are below need them, (Horton Hot Rods info) ,most above don't, but I'd say that's your problem. All GM minivans that I've worked on have them from the factory, their mc is high.
If your master cylinder is below or equal to your caliper bleeders you will definitely need them. They hold a slight pressure in the lines, and will keep your pedal up. I ran into the same problem on my 31' a few years back. You being a Westerner :), should able to find a pair from an old...