Steve, FWIW, every
oil leak I've ever had (several) on my FE in the last eight years looked like it was from the rear main seal (which it never was). Fix every other known leak, like your fuel pump, first. If it really is your RMS, can you not get your pan off with a Kirkham with the engine in the car? Even if it was tricky, and getting a seal back on the pan was hard, I would take a crack at replacing the RMS from down below first. You can always pull the engine if you have to. Replacing the RMS from down below is discussed all the time over on the Ford FE forum. But I understand that if you can't get to it, you can't get to it. Here's a typical thread on slipping the RMS in from down below:
332-428 Ford FE Engine Forum: Rear main seal