RETURNING
Luffy, Zoro, Nami, Usopp, Sanji, Chopper, Crocodile, Jimbei, Hancock, Mihawk, Kuma, Blackbeard, Whitebeard, Ace, Akainu, Aokiji, Kizaru, Magellan, Buggy, Ivankov
NEW
Robin, Franky, Brook, Lucci, Eneru, Moria, Shanks, Smoker, Bon Clay, Law, Kid, Perona, Arlong, Krieg, Hodi, Vander Decken, Caribou, Mr. 3, Garp, and Shiki
POSSIBLE ALTERNATES
Vivi, Marco, Jozu, Kaku, Kuro, Foxy, Wapol, Sengoku, Rayleigh, Daz Bones
They did say 40+ characters, so there is the chance of more than 20 new characters; I tend to think there will be a few more, in which case I would add Rayleigh, Marco, Kuro, Foxy, Wapol from the bottom list. If only it was 50 characters….
At the very least, Lucci, Eneru, Moria, Shanks, Smoker, and Bon Clay seem like definite additions.