To be honest, I think those are even a little bit too small, especially the drawn one. There's no reason why Ridley can't be the largest character in the cast by a decent margin, just as long as he isn't humungous.
Make him crawling on all fours as his default standing animation, ala Metroid Prime 3, and have him about Bowser's height at that point, maybe a little bit shorter. Then he opens up in the air and is all big tail hitboxes and general domination. I mean, even as a really big character he wouldn't necessarily have too huge of a reach, nothing much more than Charizard's Nair or Mewtwo's tail moves in PM. Plus, like Mewtwo, he could be hit when he sticks his tail out, making his large hitboxes also a detriment.
Grounded Ridley could play much more defensively, keeping himself close and just getting people away. Aerial Ridley, on the other hand, would be much more antagonistic. Really, PM!Charizard has a playstyle that would suit Ridley really well - just make him larger and maybe even a bit lighter.
Ridley not having a tail in the Melee opening is blowing my mind btw. Like what.