Who's making it into SC6? At this point, 95% of the franchise's roster is a pretty sure thing- Ivy, Kilik, Mits, Nightmare, Soph, Xianghua, Zas, Talim, Voldo, Taki, Yoshi, Maxi, Cervantes, Asteroth, Hwang/Yun-Sung, Tira- they're all gonna be in, almost certainly in the base game, and if not absolutely as DLC.
Similarly- Abyss, Algol, Charade, Elysium, Leixia, Natsu, Necrid, Night Terror, Ocladan, Patro, Pyrr, Viola, Xiba, Dampierre, Edge Master- they're out. Likely some sort of Charade/Elysium character will show up for those who like to roll random, but these people ain't showing.
Then there's your list of people we'd all like to see and theoretically have a shot, but we no one will be very surprised when they don't make it- Amy, Seong Mi-Na, Hilde, Rock, Setsuka. They all either lack the fan base or are too young to fit the time period (aka Amy. That being said, if anyone them will make it, its Amy. Her style is very popular and I can totally see them just saying "ya whatever timeline shimeline" and throwing her in).
Which leaves us with Rafael, Cassandra, and the Lizardman. Three characters that lack the the hordes of fans Talim's got, but still have a dedicated fanbase and have been series staples since 2.
What will become of these guys? Frankly, I think this question is the hardest to answer of any when it comes to this game. All three are so iconic it would seem insane not to include them, but there are no leaks to support their inclusion, no obvious winks from the devs.
What will bwcome of them? Thoughts? Personally I think they'd be crazy not to include all three (and personally devastated if they leave out Rafael) but they've been known to do crazy things before...