The Setter dump, otherwise called an attack on 2, is basically the setter ‘spiking’ their touch instead of setting it, because they typically touch the ball second, after the receivers, so it’s touch number 2, and what’s number 2? Well that’s a dump. And a setter dump is legal since setters are in front of the attacking line, since you can’t jump or attack next to the net if you’re in the back line, you have to jump from halfway down your half, that’s called a ‘backrow attack’.
Typing comments as I watch the video: 4:15 - as they are right now, given the current formation of Nekoma, Hinata can't really fake them out. Nekoma has their blockers shifted to one side, and if Hinata goes to the other side, only one blocker is sent to chase him. The other blockers are covering everywhere else 4:48 - That's a feint, not a dump. A dump is when you send it over on the 2nd touch. A feint is anytime the ball is tipped over, regardless of what touch it's on, but usually on the 3rd touch. 7:39 - I believe you get two timeouts per set
