Way too many characters in that roster.
I'd probably go
0. At lease three OC's (the twins and Darios (pic is floating on twitter but he looks playable)
1. Marth/Caeda/Tiki (as definites)Navarre (likely but sword)Minerva
2. Chrom/Lucina/Robin (both versions)/Adult Tiki/Tharja
3. Xander/Ryoma/Corrins (both versions)/Takumi/Camilla
Chrom/Lucina/Marth is an obvious choice, but they are so close in design, I'm really interested in how they make them play. Especially after adding two more OC bland sword users.
Then we have:
Lord (Chrom, Lucina, Marth)
Pegasus Knight (Caeda)
Wyvern Rider (Minerva, Camilla)
Manakete / Dragon (Tiki, Corrin)
Myrmidon / Swordmaster (Navarre, Ryoma)
Mage (Robin, Tharja)
Archer (Takumi)
Paladin (Xander)
That's actually quite a diverse cast when it comes to play styles / class representation.
Definitely lacks Axe-Wielders, which makes me think that Hector is a given at this point, unless they reclass someone else.
Another thing would be Armoured Units, which gives Draug and Effie a good chance (and Hector again!).
Lance Wielders are completely absent, so Ephraim or bust. (Will probably be Abel / Cain instead)
Do you think they would include Healers somehow?
If they want to add some more of the Fates classes, a Butler / Maid would be likely, possibly also a Ninja / Assassin / Thief.
Other interesting classes could be Villager as some form of Joker class that wields everything, and Dancer (not sure how they'd implement that, but they should at least try).
Shadow Dragon also had unique classes like Pirate (Corsair) or Hunter, and last but not least Ballistician.
Let's not forget Brides and Witches.
I think they will try to diversify the class representation, which should allow for some interesting character choices down the line.