I really don't buy this 25th of April stuff for Smash because I don't believe for a second Atlus would dictate Smash release timing nor would Nintendo let them handle the marketing of it. It just doesn"t make sense to me other than "well it kind of fits".
I didn't say that Nintendo would let them handle the marketing, but just that the release dates happened to fit. The 25th is a thursday, it's right "before the end of april" (which is the official release date) and would probably be amplified by the general Persona 5 hype of that day.