I'm pretty sure a triple announcement is not going to happen... Maybe a double announcement, just to keep the fans hooked to the game even after the fighter pass (and this is not even guaranteed); but a triple one is impossible.
Also I'm a bit skeptical about this Dante thing. The tweet is clear, they say these dates are important for news about new features of a specific DMC game, not Smash. The tweet is too specific, it's not Smash.
But Dante can be in Smash regardless of the tweet, it's not a confirmation but also not a deconfirmation of anything.
I honestly have no idea of who can be the newcomer. Last time, when we knew it was an SNK character, I said it was going to be Metal Slug because we already got Ken as fighting game character and King of Fighters was unlikely; at the end it was Terry and I was wrong.
This means, by the same logic, I would say no JRPG character, but it can turn to be one, because they don't care of balancing the representation.
Considering how Sakurai seems to love characters who seem to come out from a shonen anime or something close to it, Dante, Travis and KOS-MOS are all possible IMO.
There's an high chance it will be someone I care absolutely nothing about, as always. I hope first parties will be considered, at least for fighter pass 2.