Regarding ATT Speed and Inner Ability

Extreme Green Potions break the speed cap for all classes, so on a class that normally would cap at faster(2), a green potion will allow them to pass that. Once they break the cap you can stack on as many attack speed buffs as you can find and they'll all work (Adv Yellow Aura, Speed Infusion, Mu Lung Dojo buff, Inner Ability...)

I did some testing with it and they all worked together, it got to a point where you attack so fast that the animation actually stops showing up for a couple of attacks lol

This was on my Dual Blade btw, I'm trying to cube a glove for decent SI to make more use of this xD

Wow, Nexon... Gotta love it when they give bug fixing assignments to new hires (or old ones who don't know much about the game).
Somebody got the "make MPE Green Potions work" assignment, and made them work no matter what.
(But, conversely, someone got the "make Ambition give MDef Ignore" assignment - and made it give only MDef ignore...
We win some, we lose some).