Very compelling argument for the future Damian theory.
Question:
Why would Damian frame Kate? He likely doesn't have something personal against her or against any Manhunter. Was it one of those time travel things where he needed Kate involved so that Damian would ... get hold of her staff? Some element to fit into place to ensure his future? Is that enough of a reason for Damian to use that Manhunter symbol as his own? Instead of a past Manhunter, he's the future Manhunter before becoming Leviathan?