I get invalid objectID for A2C94. I clicked the ground before entering it. Also tried the prid command before that. Looks like I'm restarting.
That didn't work as that is the reference code for Lydia. To clone requires the
base ID, but you do NOT want to clone a named NPC. It just leads to trouble. Glad you found a resolution, though.
You can set an NPC to essential with the
setessential 1 command. For example, making Lydia immortal would use
setessential a2c8e 1Useful info on http://www.uesp.net/wiki/Skyrim:Console#Targeted_Commands at UESP Wiki.