Dogmeat is a recurring gag in the series. I could see him making yet another return.
Amata? She's hardly all that important. 15-20 minutes of my playtime per playthrough is spent with her visible, and she does absolutely nothing noteworthy as far as Vegas is concerned. I could MAYBE see a passing reference to Project Purty, though. Like, for example, this NPC/NPC dialogue:
NPC 1: Did you hear? They figured out how to purify water on the east coast. Large scale. I hear they're just giving it away they have so much of it.
NPC 2: That's awesome. Hey, did you notice the big horners were a little more aggressive than normal?
NPC1: Yeah, I did. NCR said they were gonna put somebody on that but I have my doubts...