Legends confirmed so far ~
Victini ~ Liberty Island is Accessible
Regigigas ~ There is a picture with it in it
Regirock, Regice & Registeel ~ If regigigas is available, so are they
Uxie ~ There is a picture with it in it
Azelf & Mespirit ~ If Uxie is in, so are they
Cresselia ~ Information & The item which is used to get Cresselia has been shown
Darkrai ~ If cresselia is in I don't see why Darkrai shouldn't. But it's a bit unlikely since it's an event. But we will see!
Black/White kyurem ~ The main legendary of the game. (Although, it states you can't catch the first time around. So do you catch it as normal Kyurem later and transform it somehow?)
Heatran ~ Most likely in the game due to Bianca mentioning it
Cobalion, Virizion, & Terrakion ~ Shown in pictures, also in the starting clip
Tornadus, Thundurus & Landlorus ~ They have new formes, so I don't see why they would excluded them from being found in game.
Keledo ~ Event
Meloetta ~ Event
Genesect ~ Possible release during this game's lifetime so Event