Neutral or +spd -Hp Brave Celica ???

+SPD -HP IMO. B!Celica is first, and foremost, an offensive unit and any extra Speed (which goes up to 45 with a boon) is valuable to her. HP is a superbane, and will greatly impact her defensive performance, but with DB 4 and Double Lion she should kill her opponent before they counterattack in most cases.
If you're concerned about Arena score, then go neutral just to avoid the superbane.

Have you looked at B.Celica's character page? Do you agree with what's written there?

Note to frequent responders: check his site history.

Hp superbane wont drop her bst bin, i suggest go for +spd