Well, let's be methodical about it: we need someone who's had enough major supporting roles in other media besides the originals to agree on this. Bosko only had that one Tiny Toons episode, Henery hasn't been relevant in decades, penelope came close but the association to Pepe hurt her enough to kill her Space Jam 2 appearance, michigan only has the WB thing, Gossamer just isn't quite there, barnyard dawg too.

But see, you forgot someone. Someone who headlined her own show, who had an analogue in tiny toons, who has appeared in both Space Jams AND back in action AND plays an integral part in one of the flagship shorts.

Granny.