There are several non-heteronormative Disney characters already if you include Marvel and Star Wars. It's only a matter of time before a animated character is added, although I think the pushback would still be substantial at this point.
I think @old lady should give her opinion, since she asked.
I don't know who this Eliza person is. Elisa Maza from Gargoyles? Eliza Fletcher from Phineas and Ferb? Eliza from the recent Disney Zombies movie?