I'm surprised you can't tell that this is pretty much the first visual representation of a concept long used in yukkuri fanfiction, "Stalk born bodied yukkuris", it's not anything "different or new", also, i don't think it's a premature yukkuri either, Bodied yukkuris may be easily taller than average yukkuris, but if they are born from a stalk, expect them to be small, before growing up into taller creatures after being born and developing like any baby.
there was one in yukkuri fanfic translation group, it was about this hermit guy being bothered by yukkuris and learning through them about how they had "uneasy bodied kids" so the hermit forces them to show him where they left htem, and after finding them he kills them off and take the bodied yukkuris with him, it is implied that they were born in a stalk way.
the half-youkai thing was mainly Poweryoga's idea, it isn't usually done in other works, bodied yukkuris are just that, yukkuris that become bodied instead of silly heads, of course, this all lead to some huge ammount of retarded discrimination and blatlant racism from the average yukkuris.