Finally got around to do some more testing:

1. Great
2. Great
3. Great
4. Good on paper, but still breaks some sucker tubes in levels without a floor. Last time I checked Nature's plot of land by Ragnarok, and the exit sucker tube throws you into a floor below. Hopefully fixed in 5.13.
5.Great
6. Great
7. I can't find notes on what 7 used to be, but I guess it's fine.
8. Great change, although in one use case i would like it to be a bit less generous. When running off a platform and edging a jump, it's bad when you miss the jump, but then also immediatly waste your doublejump because you missed it. It feels like a double punishment for trying and missing the jump from an edge and can seriously mess up your trajectory. I think if you run of an edge, there must be like 1 or 2 frames where pressing jump does nothing. Same issue goes for immediatly using copter ears off a ledge instead of jumping.
9. This felt bad and strays too far from game physics. Gives too much unnecessary powe to special moves. Also allows spaz to chain sidekicks within 0 frames. Trying to wallclimb with /quirks on makes you unintentionally special move. Jumping just high enough to buttstomp on a platform makes you uninentionally special move. Jumping needs to take priority a few frames when sliding or landing. I'm in favour of not introducing this at all, not even as a toggle, for jj2 consistency in behavior.