Q: Can somebody win with the Goal 5 Keepers if there is a Keeper Limit of less than 5?

A: Yes, it can be done. Since the Keeper Limit rule only kicks in at the end of a player’s turn, you could play several Keepers during your turn, bringing your total to 5 and thus winning, before reaching the end-of-turn moment when you’d need to discard down to the number of Keepers indicated by the Keeper Limit.