i'm sure you probably know about
The Negro Leagues Book - edited by Dick Clark & Larry Lester. It has rosters of the Negro Leagues from the 1880's until 1955. Pretty spendy last time i saw it an Amazon though and i'm pretty certain it's out of print. Still it's an amazing source of info, if it could be found in a library. Just a heads up in case you didn't know about it.
i'd LOVE it if you and Big Rod could figure out how to get those players into the OOTP. Just a question. Would it be as a minor league, or as a feeder or a quickstart, or ???? ? If it wasn't a minor i'd have to figure out how to use those other options to get the players included into the regular game. i'm certain there are tutorials out there.
Good luck and looking forward to your progress. Thanks for the info and all your efforts. This place & you guys are amazing.