So, could it be possible to get Half-Yukkuris or Quarter-Yukkuris if a Yukkuri impregnates a human female? At least I know that it works the other way round (a human male impregnating a Yukkuri).
Probably not, as a human and yukkuri are entirely different... and I think the picture with a pregnant yukkuri was a single done by rorinko. In the case where a male impregnates a yukkuri, that's kind of plausible, but bean-paste going into a human and causing pregnancy is a bit more far-fetched...