I really don't think we're getting another guessing game. If Amiibo theory is right, we're getting a character in early to mid-March. We've had gaps far longer than two to three weeks between trailer and Sakurai Presents/release for Smash DLC in the past.
In terms of the character, I think it's either Lloyd or Ryu Hayabusa. If not one of those two, probably a Gen 8 Pokemon (hopefully not a starter, nothing against their fans I just want Pokemon's recent representation in Smash to branch out from the pattern of choosing the final form starter that the Pokemon Company is most invested in).
Other predictions? I think the 3D Kirby, Fire Emblem Remake that got moved from 3DS to Switch, and a 35th Zelda collection are safe guesses. The most I can see for BotW 2 is another teaser, as it's most likely going to get the biggest spotlight at E3 ala BotW1 in 2016, Super Mario Odyssey in 2017, and Smash Ultimate in 2018.