Honestly, the focus should be on Nintendo Switch Online for this presentation. We are now WEEKS away from this getting out; and we haven't seen much shown off in detail. And outside of Hulu and a comic app, we have virtually no information on certain Apps that have been long requested for Nintendo Switch.
As far as SNES, I get the feeling from the data leak of button symbols, that they are going to have SNES come as soon as possible; but that it's not going to be there at launch. Gut feeling, I know; but I do think they will try to get SNES onto the service.
When it comes to Smash, I'm just thinking they are going to show Spirits. It's the one major thing that we don't know of yet, and considering we got a huge direct about a lot of Smash, seeing Spirits left out has me curious to know what it entails (and I'm just calling that hidden mode Spirits for now).
That said, if there is a fighter reveal; my bet lies to that being through a connection to the invigoration of cross play.