Two Philip head screws that hold the rotor

I was helping my nephew do a brake job on his Honda Accord. We noticed that there were two Philip head screws that hold the rotor onto this plate. Who ever owned this car before stripped the screws. We had to go buy an easy out tool. We got three out of the four screws. The one screw we had to drill out which we messed up the threads. My questions are. Do we have to put 2 screws in or is one fine? If we do have to put both screws in on each side can we tap the one we messed up? Can I purchase the part that we messed up? Is this piece easy to take off?

Please help!
Guy