Okay... Oldest bracket since I'm not actually a toddlercon but that overlaps with my area of interest.
Since I want one who stays young, that means celestials or elves. Since none of the celestials really specifically caught my eye, I'll go elf. Girl, since that's my preference.
Natural/normal physicality.
Relaxed would fit best with me, and cuddly would be nice. Excitable and demanding but accepting would be good too. And lustful, for the obvious reason.
Oh, I can pay a point for immortality for both of us anyway. Well, I'll take that even if she'll reach puberty in a hundred years, that's fine. After enough time, I'll probably be ready to adopt another anyway. As for the others, I guess reincarnating as an oni would be a power boost to me, and also normalization is needed. With the rest, I'll take the money. That's still enough to buy a house, most places.