Can one fuel pump be replaced and then need a secondary one replaced?

Yes, on these dual fuel pump systems one pump is just as susceptible to failure as the other. I find it somewhat odd that both weren’t replaced at same time - especially at a dealership. Perhaps you should question that fact. Additionally I see very low vehicle milage posted so I must assume your T-Bird sits around most of the time - this can lead to condensation build up in the fuel tank - more pronounced unless tank is FULL .. I recommend having trusted local auto repair facility evaluate the issue for a second opinion - plus repair estimates. Good luck!