So not the triumphant update that I was hoping to write this evening, but I did get closer to resolving my fueling issues. I'm pretty sure I have said it before, but I do absolutely love this site and all the helpful members.
I was able to obtain a Nissan fuel pump and damper from a fellow member here that no longer needed the setup. This made me extremely happy, as I want to keep my 280Z as close to stock as possible, and I did discover a problem with my damper.
I installed the new-to-me fuel pump on Friday and was able to test start the car on Saturday. It only took a few seconds to start! After warming up, a few throttle pushes to redline, and I had no more hesitation, and fuel supply pressure was right where it was supposed to be around ~35-36 PSIG. I think my whole neighborhood heard my shouts of jubilation. I then went to the rear of the car to check for leaks and found a steady stream dripping from above the fuel pump and into my bucket. I shut the car off and found my damper to be leaking. Luckily, I had the replacement one on hand, so I had to disassemble everything and install the other damper. I suspect my existing damper was on its way out, and the increased pressure from the factory pump (remember the aftermarket one that was installed by a PO registered around 12 PSIG less than OEM) blew a seal or something out? Anyway, everything is back together, but I am now waiting on an appropriate fuel line clamp at the pump discharge (PO used the wrong type and all the spare correct ones I have are too small), which should be here tomorrow.