Well, two of them are projectiles, whose theme is more of a cross-cultural "ouch". As for the others, in addition to Pionpi, we have its far more rarely seen fellow resident of the Chai Kingdom, the Pom-Pom Flower (better known as Slowdown McGee), though I must admit I'd prefer if they weren't so heavily used in this world, as I was sort of using them as one of the central gimmicks of my level, possibly going to far as the place decorative FG objects which look like immature, non-ambulatory versions of them in order to suggest that this collection of rocky islets serves as a spawning ground for them. Then again, your stage is immediately before mine, and of a somewhat related theme, so if you'd like to throw a couple in there as hint of things to come, by all means go ahead (I'd rather you didn't put any underwater, though, as I sort of have a gag in my stage where they keep falling into the ocean in the first part of the level, and then show up underwater in the second part).
My third non-projectile sprite is a Gao which was modified to fire a bit more slowly, and to look like...well, something more thematically appropriate, but probably not suitable for your level. Feel free to use the sprite if it suits you, but I have a strong suspicion you'll want to draw your own graphics if you do so. Though I'd imagine that's a task you're more than capable of.
Bear in mind, though, that I've remapped the graphics for these in weird ways to try to get them to work better with each other, so it could potentially cause some interference. It might also be a good idea if we didn't have too many repeating enemies in both our adjacent stages, but there's certainly no harm in one or two, especially if they're used in different ways.
Another possibility you might want to consider is AxemJinx's Mini Porcu-Puffer, which, ah, nobody's actually coded yet, but which seems like an interesting idea. Admittedly the Asia connection is a little more tenuous there, a certain infamous Japanese dish aside, but it might be a good possibility idea for adding a bit of variety to an underwater section...if, y'know, anyone ever gets around to making it.