[NoOne]

you'd have to create a league with historical teams, which you can do. the manual provides all the answers on that. pick out the team and year, then import it.

you can't easily supplant these teams in a continuious sim, though.. if you want different teams every year, you may want to just create new leagues for each structure....

if players stay retired, you could safely "retire" the previous year's players. then import the next batch and keep that team history together.

you could import new historical teams each year and replace, too, but likely have to do some other things to keep history together or separate depending on your preferences etc... and things similar. possible, but you almost certainly need to do some maintenance every single sim-year to make it work.

you can make a schedule any way you want to. changing one team's schedule without creating a whole schedule would be a pain, but possible.

you'd have to go in and change the matchups just for the mets every game, then adjust the schedule of whom they previously were scheduled against each day too. spreadsheet skills can help here, but still a pain.

you could see if a schedule like that exists - check mods forums, there is a huge list of custom schedules, or even request one be made... it'd most likely be 2g vs every team for all, as opposed to just the mets, if that matters and exists.

you can change this in-game too by hand... that would take forever. then, export your work to save it. can re-import in future with same structured league.

do the export thing with any customizations to the schedule. if you make one, keep a backup copy too.