The only thing that matters with the Kaido SBS is if Oda includes anything of the form of "he is known as", "said to be" or "people say".
That's the source of almost all the doubt about Kaido's "title".
If he definitively says "Kaido is the World's Strongest Creature", then his top 1. Otherwise, he most likely isn't.
I guess we have to wait for Viz to answer this question.