Thanks very much for the input and overview on the brake work. Got the new booster in. This pic of the old one shows how it revealed the master cylinder was leaking. The amount of brake fluid that poured out of it revealed why the reservoir wasn't showing any fluid loss- there was nowhere for it to go! The booster was already full of fluid.

I had just mailed back the $30 Cardone Master Cylinder I found on Amazon as the mechanic I checked with said it was not necessary to replace it when I put on the booster. I asked him if it was a good idea to do both at once if you are changing the booster and he said no you do not need to. I said just the booster then. And he said yes as the tests all indicated master cylinder was not failing. Unfortunately, he did not mention the possibility that even when it passes all of the MC tests it may still be bad, leaking UNDER the place it connects in a way that is not detectable (no loss of fluid from reservoir, no visible or felt leaks of any kind at the cylinder or the booster with everything assembled.) Did not want to wait for the part to reorder, so paid twice as much $60 to get an O'Reilly Brake Best Select same day and get it put back together. Thought the Cardone was probably better part than the O'Reilly part, but that was the cost of the lesson. Hopefully it will be alright.

The fortunately thing was as Toecutter said the system wasn't opened anywhere at the lines, so there was no need to bleed. Bench bled the MC well, put it together, and had brakes again. Thanks, again, to the input and help here. Turned out to be a good brake thread with helpful pics and tips.

 

I pulled the whole discussion about the brake-lamp failure out to it's own thread because I thought it made sense to be a separate topic.