Umm...a lot of these things aren't...really...mascots.
Mascots require being something, often not human, to be representative of a series. Like, you think a series, its something that comes to mind (I know, its not exactly that, but you get the idea.)
Something like Moogles of an FF game is a mascot. Wyverns of FEs, especially since Wyverns are just shy of being in the same tier as Dragons for "common RPG Enemies" are not.
I dunno, there's a large amount of arbitrariness chosen for that. I mean, Mermaids from Suiko4, but not things like Kobolds or Ducks from previous Suikos? Or Beavers from Suiko 5?
Not to mention I object to Epona being on the list in general, to just avoid all the "OMG ZELDA ISn'T AN RPG!" debates <_<