1) Is there a way to get DT for crature or npc ? there are only DamageResist stats to use with GetActorValue could be with NVSE

2) for creature in geck there are only combat skill and via GetActorValue i can take each one of normal skill so is combat skill calculated by normal skill and there are still hidden normal skill for creatures ?

Getactorvalue damagethreshold should return the DT of your currently selected object. Combat skill determines a creatures other skills related to combat, such as energyweapons, guns, explosives etc.

Hope this helps.