Here are my thoughts on newcomer odds:
: Very likely, since Bayonetta's third game is still Nintendo exclusive, and her two are being ported in the Nintendo Switch.
: Guaranteed at this point.
: I can see this one somewhat likely, because Square Enix has put games on the Nintendo Switch before. Plus they seem fine with Cloud in Smash 4.
: I know people bring the argument that she was used to bring up an upcoming game, but I say that she is still likely due to being quite a popular FE character.
: Easy to make, so I can see him being likely.
: Just too related to Nintendo and too iconic.
: With it's popularity increasing even more, I am sure this will be in Smash for Switch.
: Same with Duck Hunt's case.
: Easy to make like Dark Pit and is popular with the Fire Emblem series, so she is highly likely.
: Seems likely to return, considering Capcom has games that include Mega Man planned for the Switch.
: As much as people dislike these, they are coming back either way. Miis are in the Nintendo Switch and they will always be among Nintendo, so they are very likely.
: Likely to return, just because of how iconic he is. If Bandai Namco is developing the game again, Pac-Man is even more likely. Bandai Namco could be developing the game, because they are developing Metroid Prime 4.
: Highly probable, especially if Sakurai is developing the next game. She is the second most important Kid Icarus character.
: Honestly, hard to say. Smash 4 saved Robin's chance, so he/she will make a return I am sure.
: Also guaranteed. Popular, you get the point.
: All depends on Capcom, but Ryu is likely to make a return.
: You know, Shulk actually has a chance of returning. People say that he is going to be replaced by Rex / Pyra, but I say that he will hopefully he will still be in Smash for Switch. He may be done with being in games, but Shulk will always remain the starter the Xenoblade Chronicles series. Plus ROB got in and it has no games of itself anymore.
: Pfft, easily returning.
: Her games did very well with profit, and she is still popular. Despite being a "Wii" type of character, I say she has a good chance.