Persona 5. That survey that SE did is most likely for Japan than the rest of the world since Persona 5 is coming out only in Japan in the summer and most likely winter everywhere else except Europe most likely.
Persona 5 will get trounced in sales WW but in Japan it will be somewhat close so I imagine Atlus and SE are trying to stagger the releases without eating into each other's money.
This is true and in NA FFXV will sell like crazy. Persona is the same game and makes improvements over time while FF changes. There might be a lot more new fans for FFXV considering it's almost 10 years plus of all the news about it.