NISA localized Generation of Chaos: Pandora's Reflection for the PSP in 2013. There is no way they're skipping Coven for the Vita in 2018. I think this is all just a ploy to hype Coven as NISA's last, greatest Vita title.
While I do believe Coven is coming, I don't think it's a ploy. Anihawk said NISA didn't even consider bringing Coven over a few months back. It simply wasn't on their radar. For some baffling reason.