Very thorough and full of useful tips. There are several things i wanna add, though
Inkzooka: the higher you aim, the longer the shot would travel, but it might not hit opponent right in front of you
Kraken and Bubbler: can eat opponent's Splat Bomb and Suction Bomb
Kraken:
Use) note that Swim Speed Up does not increase your squid jumping speed so spamming jump actually makes you go slower. While swimming, if you bump into hiding squid your gamepad will vibrate a little and if youre fast enough to press X you will still splat him.
Counter) shooting at jumping Kraken will negate almost all his momentum, this is especially useful at certain terrain, for example Mahi2 Resort while jumping over water, and Flounder Heights while jumping over the center of the map
Inkstrike and Killer Wail: Special Duration Up will decrease the delay after using the special