No offence but good god that sounds like the worse idea i've ever heard for a Castlevania storyline. Its just completely ridiculous when you consider it.
None taken. And yeah, it's pretty corny. Hey, it's not completely my idea; I'm just inferring from what little information we were given. All signs point to this happening (that is, if the two DLCs are in chronological order, or as best they can be for using time travel). And it's not like the writing and story aren't already terrible to begin with; at least this way we have something resembling a real Dracula fight, yes? Keep in mind the... uh.. whatever R word they used for the future scenario was said to have a battle with "a notorious enemy". (And this way, Dracula might end up becoming someone else.) The original ending and this kind of conclusion just scream Hideo Kojima, though. I'm sure it was his idea.
Of course, it could also be that I'm completely wrong, and maybe Gabeula ends up fighting ZoDeath. But it seems like that would not only go against Gabeula's desire to die, but also require a completely new character moveset for one DLC chapter, which wouldn't be the best use of resources.
But of course, this would also point against Gabeula putting up a fight against Gabriel... I guess we'll have to wait and see what actually happens.