Let me think a bit. People have been clamoring for Octolings since, what what it, August of 2015? And they only got louder after S2 came out featuring an Octoling as a semi-important (at the time) NPC? And then we got the DLC, which not only has probably the best single-player mode and story this series has seen yet, but also finally gave us/them not just playable Octolings, but playable Octobois as well?
No quick maths required here. There is absolutely no way Team Octo is getting sub-60% in popularity. Hell, they'll have enough of a man Octoling advantage that I wouldn't be surprised if that alone allows them to get at least one win category.
As for which team I pick... well, I'd like to win, and I'm a natural contrarian, so I'm wont to side with Team Squid on that alone. It means giving up the sweet afro I have currently, but eh. Ya make do.
Although, the "worldwide" bit concerns me. Granted, I am certain that Nintendo's servers can handle it, but all the same...