I imagine the anims.j2a file could be hacked and unused sprites put in place of used ones (don't quote me on that, though; I know little to nothing about our capacity to hack this game). However, we couldn't use Tweedle or any of the other scrapped sprites as they were intended to be used, because the programming that would make them work isn't in the game's code. (Again, as far as I know, which is not far) So for instance, Tweedle has no behaviour, (although his sprites seem to indicate he would have been a very interesting foe to battle) and the potions and what have you have no function.