I suspect that the power of various TFB cards may be either buffed or nerfed depending on the set. Like, depending on what's available, you either don't want to put any cards in the trash (for your opponent to use somehow) or you want to combo a TFB card with something that counts the trash yourself.
I suspect Apprentice will be buffed, since it's nonterminal, so if there's an action card that cares about the trash, you can play apprentice and then the trash-caring action. Same for Upgrade, I suspect.
How the terminal TFB cards will play will depend on whether the Dark Ages cards they match up with are terminal or nonterminal, and how many of each you need to get value out of them (is it worth building an engine just to make the combo work?)
Just speculation, of course.