I don't see Kaguya reincarnating into Hinata, but i can imagine Sakura eating the chakra fruit and beating Madara to death...
I see three main reasons for this:
1. Sakura in some aspekts reminds Kaguya...
2. Sakura obtaining power comparable to Sasuke's and Naruto's leads to "reincarnation" of "the legendary three".
3. Becoming the third power (maybe even greater than the previous two) she will be able to stop Naruto and Sasuke from confrontation after defeating Madara.
The chakra flower is going to bloom and the chakra fruit is going to ripe, thus someone must eat it.. why not Sakura?
Besides, who else fits better? She is a peaceful healer, so she will not use this power for wars.
It's a little far-fetched but hey I like the sound of it. I think it could be her also simply because of her character. The whole flower blooming thing and her hair being pink and what not.