Could someone give me a rundown on AI settings? i'm trying to pacify some creatures but i don't know if i should put Fight 0, 30 or any other value, theres also Flee, Alarm and Hello settings..

http://uesp.net/wiki/Morrowind:Fight#Fight

Tanks, so creature disposition works the same way as NPCs? minus the Taunting, Bribery, and Intimidation part..

so if i set Fight 40

They will attack when i'm within 500 units or the disposition must be 10 or less too like NPCs?

Actually, creatures don't have disposition, so the chance of attack is only determined by proximity and perhaps random numbers. As a landmark, a scrib has Fight=50 and I can't remember any scrib ever attacking me, so go figure.

in my experience, creatures start attacking at 78..88 fight. Maybe diseases/kind of creature/level(=confidence?) factor, but 90..92 fight is usually sure attack on sight.
Having said that, fight=30 seems to be the standard peaceful setting, a greater flee should make them flee depending on health/distance.
Not sure about alarm, I think alarm is ignored. Hello should be ignored or maybe used only in case your creature has filtered dialog lines, so I'd keep them to 0.
[EDIT}As usual, no magic settings, you have to experiment to find best values for each creature. Also, verify if you have mods changing AI GMST settings, they can change behavior from vanilla.