An idea came off in my mind hence wanted to ask all those experienced with scripting thsta- Is it possible to get reference of the npc or creature on player`s cursor or whom player is attacking using MWE or MWSE and use playanim function on that npc through reference??

NPCs can only play animations that are already attached to them, you cannot attach an animation to an NPC in game. You can, however, use MWSE to have an NPC play a particular animation (idle, movement, or death scene).