So I ended up upgrading to PS4 Pro after all and MLB 20 is on sale.
I'm currently using a roster in 19 from the vault with all the minor league players.
How will this affect players that have gotten facial scans/upgrades? Will only official Sony roster players get the upgrade if they even existed? Ie if they did some work on Harper in 20, will the save file of Harper in 19 look like the Harper in 20.
Hopefully this makes sense.