Just updated to the new version and got a legendary dweller called Anthony Page. I don't remember him from any of the games and can't find any references to him on the wiki. Any idea who he is? (Fallout 4 character maybe?) He has very high charisma and luck and comes with a greaser jacket.

Yeah, most likely, I got a guy named Preston Garvey, quite the badass I must say. You can actually see him in the Fallout 4 gameplay video that was shown at Gamescon.

Pretty sure that Anthony Page isn't "legendary." The list to 21 possible legendary heroes hasn't been updated, at any rate, and he's not on it. There seems to be an unlimited supply of "rare" dwellers, each of which comes with a random rare outfit, 30 base SPECIAL (distributed randomly), and it seems a randomly generated name. My guess is that your Anthony is one of these rare folks, a suspicion that is further reinforced by the fact that he showed up wearing a rare greaser outfit. Are you sure he went all golden and sparkly when you received him (I am assuming from a lunchbox)?

There are only -- or so it seems so far -- 21 named "legendary" dwellers. Each of them comes with a legendary outfit. Most of them also come with a legendary weapon, although some of them come with no weapon, and many of the "legendary" weapons they do come with are surprisingly underwhelming. And each legendary dweller comes with a total of 40 base SPECIAL fresh out of the box. Preston Garvey is definitely a legendary dweller.