…For other Actions, like Draw 3, Play 2 of Them, Inflation affects the Action in progress. For Goal Bonanza, one can easily draw an extra card, but does Inflation retroactively affect how may Goals one needs to have discarded? What if I don’t have an extra Goal to discard?
A: While Inflation can certainly increase a Draw or Play requirement, it’s not possible to have it retroactively affect any discard requirement, since, as pointed out, there’s no guarantee a player will have an extra Goal (or whatever) to throw away. So, in this case, you would not be required to discard an extra Goal to get the extra draw and subsequent play.
Note that 5 Card Mission is the Meta Rule equivalent of the regular New Rule Goal Bonanza, and the Black Knight expansion for Monty Python also has a New Rule called It’s a Quest, which works in much the same way as Goal Bonanza (except it’s discard 3 Goals, and draw 4 cards to play).