Is it possible to edit these ROMs and change the players and their stats? And if so how would a person go about doing it and how hard would it be? Thanks.
I'm sure it would be possible to edit the hitter and pitcher stats, but it would be quite a bit of work. You'd have to be familiar with the workings on NES ROMs and know where the data is stored. I'm pretty sure all the data is stored in a different way, meaning most of the work done on the original RBI would be lost...
So it can be done but would take a decent committment from someone who has worked with NES data ROMs before....