Just giving a fast access of my favorite command (i've been looking for this command for 2 weeks P.S. thnx for the Admin Commands so i finally figured it out)
Setting the NPC to do the command you want: set (NPC name) orders (command)
Making the NPC invincible or not: set (NPC name) binvincible true (or false to be not invincible)
P.S. pls dont delete this post. i bookmarked this page for me to remember this hardworking researching thing to end.