You've got it! There are no Special NPCs in the pix because you have to summon them using amiibo cards if you want to deco their homes. They're not findable/unlockable on Main Street.
I'm not sure which guide you're referring to (do you mean the game guides released in Japan?). There's a thread in this forum somewhere that shows a screenshot someone found of all villagers/Special NPCs we will supposedly eventually see, though as far as I'm aware its authenticity has not been confirmed. Best I can suggest at the moment, without knowing which guide you're referring to, is that there are a couple of threads with links to lists of known amiibo cards in the first 2 series (there will be 4 series in total of 100 cards each). For series 2, look for a recent thread with "series 2" in the title. It links to Nintendo of Japan's list of cards (though not all of series 2 is revealed yet). For series 1, the "Frequently Asked Questions" thread includes a link to all of series 1 in the "amiibo card info" section.
Hope that helps somewhat!