>>32842442Considering Ultra Sun and Moon are just filler, early 2018 seems plausible. Even though I'd love for them to release the Sinnoh remakes on the Switch, it'll probably be a new generation to make a bigger deal out of it. A December 2018 or early 2019 release is the most razonable expectation for them to come up with the games.
The teases will start as soon as they make the first town, just so the Switch hype won't end, as they did with TLOZ: BOTW. Let's just hope they won't do the same thing that happened with the Wii U.