I think if you can get them trained and have the space to over winter when you put them back in the spring they will be used to the pellets and continue to eat them.
I think they will eat some minnows and BG as well but when the feed comes out they will take the easy meal.
Especially if they are larger than 2 inches or were acclimated to live feed before feed training. Additionally I have found a certain percentage of feed trained bass revert to natural feed exclusively, and even the regular feed trained bass won't pass up an easy live meal.