OK. simmed a whole year. A couple things i did differently. One i didn't delete the players from the Mexican League, as i knew there weren't enough FA and incoming 1901 players to fill 16 more teams. Of course, all the players i kept were fictional. As this is just a test to see if Negro Leaguers and MiLB show up, it didn't matter.
i allowed posting, though it won't take effect for a while, as all players are in 1st year on contracts in Mexican league it seems.
i allowed selling of players (either i am getting blurry eyed or something but had a heck of a time finding that option.)
No color barrier.
A lot of the early year players, such as Albert Toney and Home Run Grant didn't appear - but i imported them. i only checked a few Negro League players from a list i have. as well as a couple of Minor League ball players, and they were in game (both Majors and Mexican League, as well as Free Agent pool.) i think that needs to be checked better and in more depth, but on the surface, it seems to be working.
i do not have a draft enabled, but i did see it possible to use the Mexican League as a feeder for ML draft (and vise versa, which i wouldn't want). Anyone have ideas, experience with that feature?
Anyway - the template idea does seem to work. It may need tweaking, refinement and a lot more testing. But i think potential is there.