Look in the wiki for their RefID, then open the console and input "prid (insert RefID here)" after that the npc wil be targeted, then type "moveto player" and the one you choose will be teleported to you, repeat with the other RefID and you just found both of them.
You need to consider the possibility they are dead.
Or you can just do as the above poster says. Or even just use this wiki to find their ref IDs and use "player.placeatme xxxxxxx (where xxxxxxx is the ref ID)"