Greetings,
To kill an NPC, you'll need to use the proper command: /npckill
From the Commands wiki page:
Code: Select all/npckill <world> <type>: Removes all NPCs of the specified type. The type argument can be any of the following:
all: All NPCs.
chatting: Chatting NPCs.
doctor: Doctors.
relearner: Move relearners.
shop: Shopkeepers
trader: Traders
trainer: NPC Trainers.
tutor: Move tutors.
.
For the second one: Each NPC should have a UUID, if you are able to grab that, you can teleport an NPC to a location. Most UUID can be grabbed with the NPC Editor tool in-game.