I think there are no 'Iso imitators' because his animation doesn't really have any outward feature that's easy to see, dissect and reproduce. Ohira has the wobbliness, jagged lineworkd and hyperreal faces, Hashimoto is similar but more solid/weighty and he has distinctive folds and shading (at times). Kanada had the timing and poses, and he's probably the most easily imitable animator. Of course the gimmicks most 'Kanada' guys pull off have nothing on Kanada's own animation. The super-solid guys like Inoue or Okiura have the technique, but their approach is easily understandable and some people do imitate it. And so on, even new animators like Tanaka have like thousands of copycats.
But Iso didn't really have a shtick like that. Doing all the drawings yourself doesn't tell you much about the technique, neither does using 3s and 2s alternatively (basically everyone in Japan does something like this, with different types of animation). People say his animation didn't go pose to pose but flowed better, but that's more a statement of quality rather than describing his technique.
So yeah, it's hard to 'imitate' Iso because doing so would entail being an extremely good animator. Something most copycats really aren't.