I've had two time travelers spawn on their own in my game before, the second one was nice looking as well and they weren't clones of each other. It was clearly a glitch but I was only testing out the EP and how Traveler worked with it back then and probably would not have played through that.
The time traveler is a Service Sim in addition to having the occult type (like the Grim Reaper), they can't be added to a household and I don't believe the designation can be forced on them unless you don't mind them being a homeless NPC who keeps wandering off-screen again.