Solved: I come here with my head hung in shame and totally humbled. After testing nearly every component, I decided to go through and clean every connection again. Though I had replaced the 25amp fuse connected to the battery, I apparently hadn't cleaned the connections as thoroughly as needed. It was difficult to get a pipe cleaner in the female connections within the fuse holder, but I eventually did and this seems to have solved the issue. There is now spark and fuel pump primes and runs. Car started right up. Drove it several miles. Did a few other short drives.
However, I am now back to where I started. While the car started fine. And started up several other times yesterday with no issue. It would not start this morning after sitting overnight. This is the same issue I was having previously. It will start fine within about 6 hours of a previous start, even if the engine is cold. However, longer than this, such as overnight, and it will not start. Sometimes, disconnecting and then reconnecting the fuel hose from the sender unit to the main pump will get it to start.
There was also a new problem- a rather violent jerk during hard acceleration in various gears (not sure if this is spark, injectors, clutch, or something else). Back to the drawing board.
But I want to thank all the helpful posters in this thread. Have learned a lot about the interplay of the various electronic components as a result.