ArcanicNeon said
what do you mean when you said that dallas will need to be Vetted?
Well, Hayley doesn't know who Dallas is, and neither does Tenpenny or House. All they know is that Dallas somehow got his hands on the Pipboy of a person who was SUPPOSED to be on the trip. So, naturally, before Tenpenny or House would want Dallas accompanying them on an expedition of this sort, they'd want to make sure he's fit for the task.
In terms of the story, it'll probably just be a conversation between Hayley and Dallas (I may even do it "off screen' so to speak) where she gets his story, figured out what he can do, and decides that he's good to go. It's not really gonna take much effort on your part, we just need to do it for the sake of logical consistency in the story.
Sabin we don't need to do, as House clearly was aware that the NCR was sending an envoy. They were expecting someone--not Sabin specifically, but someone.