Well they made up for it with this expansion by adding a lot from Asia.I would *hardly* call them a safe bet when Machu Picchu isn't even in the game.
Unless it's a unique replacement for the Government District, it would be an odd omission to leave out a wonder so intrinsically tied to a civ.
Honestly, I wouldn't place my bets too high that every continent will get representation in R&F. I mean, between Civ V's two xpacs, Assyria was the only "Asian" civ we ever received.
As for the Inca, I'm under the impression that the palace in the capital could resemble Machu Picchu, if we don't ever get it as a wonder.