GetUnitCooldown() ?

Is there any way to know what attackspeed a unit has? (like 1.35)

Nope, just make a function and pre set it to all your units.

is there a way to make it do an ingame test? that might be inefficient tho, but you can make it attack something and time it to the next attack

Or maybe you could just check every time it attacks to when it deals damage. Then you could store that value to the hero so you can get it later.

Not sure, but dont all heroes have the same attack speed? If so, then u can use agility+item bonuses to determinate attack speed.

They don't unless you purposefuly make it that way. Paladin has 2.2, Archmage has 2.13, MK has 2.22, Blood Mage has 2.13, etc. I guess they are all pretty close to 2.2 though.. oO