2-4 feet would be fine. I don't care if it's ignoring the "canon" height given by someone with no sense of scale (or just before the games had to deal with comparing him to anything of a decent size), if it's in favour of the actual height he's shown at in the games (both Smash and the times humans have shown up in Kirby games).

Also, something I forgot to mention which is just a general simplicity's sake thing, given that we've got characters coming from different countries/planets...Translator microbes. Because RPing with massive language barrier issues tends to be more of a headache than it's worth, once you go through the portal, it'll automatically translate whatever your character hears into a language they'll understand.