Radiant Hero Ike

They could go with Hyrule Warriors Impa, though I don't know if there's licensing issues with Koei Tecmo or not.

Impa could make a good Sheik Echo, I think. Off the top of my head I dunno any other Zelda character I'd want. I mean... I still want BotW Zelda, but that ain't gonna happen. I guess uh... What's that one evil lady called? The one with blue skin and the ugly hat? She seemed cool. We don't have any female villains aside from Dark Samus.

I don't have a source for this and I might be completely wrong, but I think all the original KH characters are owned by Disney... I think it'd be up to them I'd I'm remembering things correctly. Anyways, I've been notified that Tails still appears on GHZ. He shows up around 1:14. Although he could still end up being a fighter, they could do what they did with Toon Link on the Spirit Tracks stage and have Alfonzo be in charge of the loop EDIT: Ashley was already an Assist in Smash 4, and she's still one now... Although I wonder if Lloyd is possible (even though I'd prefer a different Tales character).

I love Rex's generic "never give up" personality, I hope he's in as DLC. As for base roster I'd love a Xenoblade Chronicles X character and stage. Probably Elma and maybe one of those moving stages that goes to each of the areas (Primordia, Noctilum, etc.) And I hope Black Tar is one of the songs. :^)

Doesn't Squall use a one handed sword? That might be a problem, but he's pretty cool too. ...Despite me just saying that, Lightning would be cool even though she also uses a one handed sword, hehe

On the topic of Cloud getting an Echo, Zack makes the most sense... But I personally would like Noctis more, just because I like him more as a character. He can wield giant swords in his own game at least. But I'd be fine if they chose Zack, he's still cool too!

Man I wish Sega weren't so controlling when it came to Sonic. Him not showing up in any CG trailers and getting one new remix in Brawl is lame, not to mention his relatively muted colors. Square seems to be the same with Cloud, and I wonder if him only having a JP voice is also part of it. Anyways since Echo Fighters are a thing, if they end up adding Blaziken or something I hope Infernape could be his Echo.

Is FNAF popular in Japan? That'd probably be a deciding factor. Shovel Knight was published by Nintendo in Japan too.

Not really... Daisy, Richter, Lucina, Dark Pit and Dark Samus all have the exact same moves as another character, barring Final Smashes in some cases. Chrom is unique in that all but one of his moves are Roy's (his up special is Ike's, sort of. Different startup). Their only real differences to the characters they're based on are idle poses, taunts and voices. Even jabs, tilts, aerials and smash attacks appear to be the same. Semi-Clones are the ones with different moves (Smash 4 Roy is very different from Marth, Lucas has different properties to his Specials and almost completely original other moves, Dr. Mario has Mario Tornado and a new Dair, etc.) If Shadow were an Echo, he'd probably not get any new special moves, except possibly a new up special (which would just copy Mewtwo). Which I'd be fine with since he would playable at all.

Sonic has 6 more songs than he had in Smash 3DS and Wii U total (I paused the video at 14:31, it briefly rolls over Sonic's icon in the sound test and it says 20 songs). Hopefully one is a remix!