so my friend (american in japan) who works at nintendo (i know the meme i know) finally was able to get a glimpse of the starter promotional stands in storage they have! he didn't risk taking pics but he says the grass monkey becomes a "gorilla with xylophone abs" but "a proper gorilla not like what they've done before"
the water lizard becomes like "randall from monsters inc crossed with the phantom of the opera"
the fire rabbit becomes "sorta like an olympic runner who leaves a fire-trail where they run"

no type info or anything but he reckons since they have these in the accesible storage they must be releasing them very soon!