I know nothing about SNK or their games to be honest.
They got a lot of influential franchises, namely fighting games with Fatal Fury, King of Fighters, Samurai Shodown, Art of Fighting and some of the best Arcade animation with Metal Slug.
The two rumored characters, Nakaruru and Terry Bogard are really popular. Terry was their mascot of sorts until Kyo from King of Fighters became their main dude, but even then, Terry's popularity can't be understated.
I'm hoping for Terry, since of the few KoF and Fatal Fury games I've played, Terry's always been my main. He's cool as **** and has the BEST Engrish. Also some of the best lore of any fighting game protagonist.
That said, in recent crossovers, SNK's characters have been all over the place. Geese in Tekken, Mai in Dead or Alive, Haomaru in Soul Calibur and Terry in Fighting EX Layer. So if it WAS Nakaruru, it still wouldn't be that weird since they've used different characters per crossover in the last 3 or so years.