But whether you consider me an opponent or not doesn't change whether I threaten the square you're in, does it?![]()
I believe there is a lot of discussion on whether or not an invisible ally provides a flanking bonus since the foe doesn't perceive him to be a threat (doesn't perceive him at all).
This would be the similar path to follow for consistency, IMO. If the spectral hand does then so would the invisible ally.