Since the two new squid "sisters" have been announced, here are pop singers Pearl (white) and Marina (turquoise), substitutes for the previous two squid sisters. I bet you can guess which one the fans liked the most.
Of course, along with Splatoon 2 comes the drawing feature present in Miiverse without having Miiverse, accessible via the red mailbox in the Splatoon 2 Premiere Demo. As you'd expect from the drawings in Splatoon 1, the quality of these are... the same. Here's a news article from Kotaku showing all the fun people have had with it so far. There's, like, 2 swears in it, though.
I've also downloaded the Splatfest Premiere and it's quite fun, mostly from poking around the place and spending all but 5 seconds on whether Cake is better than Ice Cream. Since I never played the original, controlling the game is very tricky so far, but I guess that'll be resolved with a bit of practice.
The first Splatoon 2 Splatfest, Cake v. Ice Cream begins on July 15th. Splatoon 2 is set to release on July 21, 2017.