Eh, not so sure Regina will deal well with you taking Henry again. and I severely doubt that they would let Henry anywhere near Regina's jail cell.
And Regina's disinclination to share Henry isn't something she alone is guilty of - given Emma&co's doing the same.
(perhaps Regina should have recorded and replayed Snow & Charming's discussion for Henry; one of the main differences is that Regina is so proactive about not being shunted out of Henry's life, that Charming and Snow get to pretty much keep their hands clean, despite their intentions to take Henry away)
---as to her plan---
if "Storybrooke gets destroyed" should have been to Henry like "FTL gets destroyed." (and WHY does Henry not remember that?)...then Storybrooke will be fine.
Yes, I know part of the survival of FTL was because of Cora, but Henry doesn't know that - what he knows is that Regina & Charming said it was gone - then Henry learned FTL was still there and it has Snow White walking around in it.
though Cora didn't save it single-handedly... where did the Ogres and other "they have returned" things in FTL come from?