This is about to be the best Smash game ever, no doubt in my mind. It seems like Sakurai is really listening to the fanbase.
I'm still praying to every deity that has ever been worshipped in the history of mankind that Banjo-Kazooie makes it in.
A few people have pointed out that there seems to be a Heroes vs Villains theme with the new character reveals. Ridley, Dark Samus, and King K Rool, Wolf (coming back). If that theme pans out we could see Shadow the Hedgehog / Octoling as echo fighters. Maybe Tom Nook LOL (He's the Villain of Animal Crossing, right??)
I'm really happy and CH'YPE AF for everything I've seen so far. Also still hoping they release a gamecube shaped pro controller. Just do it, Nintendo. Your wallet will thank you.
Shadow's a lock for a Sonic echo. It's the same thing as Dark Samus. A character that's an "echo" of a Smash fighter in their own franchise, was previously repped as an Assist Trophy, and who hasn't shown up in any of the E3 gameplay and official media. There's no chance he doesn't happen.
Octolings seem like a pretty for sure inclusion.
I'd say Ken is another locked echo, as he's literally *THE* fighting game clone character. In a game where clones are a major content category, complete with an official name and categorization scheme, there's no way in hell you don't have Ken. I know some people are learning towards Akuma because of the whole villain thing, but it's either both or just Ken.
I'm also pretty sure Liquid Snake (again, fits the template of effectively being an echo in his own franchise, and is a villain) and Jeanne from Bayonetta will be in as well.
Less sure of these:
I feel a Kong is pretty likely (Dixie for Diddy and/or Funky for DK, especially since Funky just got brought back to the spotlight)
Maybe more Star Fox characters like Slippy and Peppy (although Fox, Falco, and Wolf are already really similar so Echoes may be overkill)
Ninten for Ness
Blood Falcon to get upgraded from a palette-swap to an Echo of Captain Falcon (or maybe even just upgrade from palette-swap to named costume?), possibly Black Shadow instead
Isabelle for Villager, especially as she's become the de facto franchise mascot
Tiki for Corrin
Ms. Pac-Man for Pac-Man (perhaps unlikely given Namco's history with her)
As far as Banjo and Kazooie goes, I've been thinking they're extremely likely for a long time. They surely poled high in the ballot, Phil Spencer wants it to happen, and Microsoft and Nintendo are closer than ever. I also think Minecraft Steve and Alex are pretty likely too.