Some of these reference victory animations, as shown in the video:
Stage Entrance – The Octoling rides in from off screen on an Inkrail and lands.
Up Taunt – Charger victory animation Girl: 0:23 Boy: 1:23 (Since this is a taunt, the Octoling Girl and Boy may share the same animation rather than using their separate ones.)
Side Taunt – Octoling opens their free hand and shows a Golden Toothpick (if you know, you know). Octoling then closes their open hand into a fist and does a small fist bump and nod with a look of determination, akin to the animation they do when a Curling Bomb that they’ve used explodes.
Down Taunt – Octoling crouches down and smiles at the camera in a similar fashion to the “pose” they do during the final cutscene of Octo-Expansion before the credits roll.
Victory Theme - Either the "Test Passed!" theme or the theme that plays when acquiring one of the 4 thangs.
Victory Pose 1 – Dualies victory animation Girl: 0:50 Boy: 1:44
Victory Pose 2 – One of the 4 thangs is seen behind Octoling as they snap a photo with it. C.Q. Cumber is seen next to the Octoling/thang and the Octoling finishes by winking at the camera.
Victory Pose 3 – Brella victory animation Girl: 0:59 Boy: 1:53
Clap Animation – I don’t know how many of you guys have seen Octoling’s losing animations in Splatoon 2, but a good amount of them are a bit overdramatic/salty. So when an Octoling loses in Smash, they’ll definitely be glaring you down as they clap.
Costumes – There are 4 Octoling Girl and 4 Octoling Boy costumes. The default for each uses the Agent 8 outfit, while the rest use various costumes from in-game. Inkling already uses 8 different ink colors, and while Octoling’s first default costume would use the magenta colored ink as seen in most Octo-Expansion promo material, the other 7 would need to use other colors. I can’t really go through all the different possible colors still available, but here’s a link with a whole bunch of them, pick your favorites:
https://splatoonwiki.org/wiki/Ink