Crystal didn't have a battle frontier, it was just a Battle Tower.
From what my friend told me, Reburst a pokemon manga that included fusing with pokemon and apparently the the logo or something has something in common with it making people think the fusion thing will be a thing.
Eh same shit
That manga is from like early B/W though, I'd more believe if it was slightly newer. But again, as long as they introduce some Pokemon that are good but not completely broken as well as some cool new moves, I'm a happy man.