If you watch the anime, they made an ep with Haribel's flash back, and in that they claimed that Haribel was a VL. Kubo has trolled the anime team a few times though so I guess we could kinda ignore it.
If you think about it, it kinda makes sense though. Stark took out 2 Vizard Captains, and had fought on par with 2 of the best captains before that. Had he not been caught off guard and injured, I'm sure he would have put up a better fight. Same could be said about Barragan, his power was crazy imba, only that he had a stupid weakness. He would have pawned Soi Fon without his release.
Yammy is the thing that stuff us up. Ranking him #0, unless his a purpose mod arrancar (though Aizen claimed Wonderwise was the only one, but Kubo trolls so) and is a nuke waiting to go off, then I don't see a point in him. Even now, I don't see why Yammy is ranked #0, especially with the way the story is going, is there even a need for an espada to remain? Especially a dumb one?