Well Bolt is Himawari's brother
NH argument : look at their head their hair
& the whiskers
Despite the fact that Himawari's haircut is similar to Lee's son xD
The only thing they have in common is the whiskers and the cherry tail thing, that's it!
Which could be very well explained by the movie. Cuz if Sakura will have the involvement I think she will, it might have very well been the case of some sort of pseudo-jinchuuriki, idk. Sakura's necklace is too much of a buz and they're hiding it.
The only necklace situation we've had in the manga is Hashirama's who was made to resonate with Mito's X Kyuubi chakra. WHY? For Hashi to make sure he can be of help to Mito if she ever gets out of control, basically.
But that's just speculation on my part anyway, we'll wait and see.
It'll be funny if Toneri is fixated on Hinata because he considers her to be his target to accomplish whatever he wants but afterwards sees Sakura being a bigger threat and he changes his objective from Hinata towards Sakura, lol! Cue explaining why Hinata's and Sakura's children have the whiskers if it's not a design feint.
The thing is that possibilities are endless here and I am not sure to which one to stick, lol!