A new trailer has appeared with more scenes and shows the main character sitting with the three other characters that were shown in CoroCoro scan.
Link to new footage: [link]
Release date October 12th
Apparently if you play as the boy character then the girl (without the hat) will become part of game and a rival and will go by the name Serena, but if you play as the girl then the boy (without the hat) will be a rival and go by the name of Calem.
The three characters shown the CoroCoro scan, the boy with the vanilish on his shirt will go by Tierno, the orange haired character is a boy named Trevor and the girl is Shauna. They will also be apparently semi rivals.
Kalos Region update
The Starting towns english name is Vaniville Town (formerly Asame town)
The town were in the trailer the character was shown sitting on the bench with the Roselia fountain is called Santalune City and is the location of the first gym which is a bug type gym run by Viola
New Pokémon, update
The Lion cub pokémon english name is Litleo
The Base form of Vivillon is called Scatterbug
The fairy pokémon that is holding a flower's english name is Flabébé. Interesting thing according to the main website this is a very tiny pokémon, its height is 0' 04" or 1/25 of an inch tall.
New Moves, update
The move Battle Cry's name has been changed to Noble Roar. It's used by Litleo
According to info from people that went to the round table discussion they revealed that you will still have the bike in the game.
Also you can perform rail grinding with rollerskates.
Older Generation Pokémon in the Game
On looking at the first video revealing Sylveon back in February showed two Pokémon Sylveon battled which were Gligar and Hariyama
Gligar and Gliscor
Makuhita and Hariyama
On closer inspection of the statue from where in an earlier trailer the female character runs past on a bridge from a palace shows a Palpitoad and as seeing that Golurk, Eevee and Dratini (they are with a Knight) that are also with the statue were seen in later trailers then its possible Palpitoad is in the game.
Tympole, Palpitoad and Seismitoad
Also three Pokemon were shown in a older trailer for Awakened Mewtwo battling him so they may be in the game so
Cranidos and Rampardos
Shellder and Cloyster
So if they are in the game then the number of older Generation Pokémon in X and Y is at 110 (as Mewtwo is an older Generation Pokémon, and assuming that Roselia and it's evolutions are in the game as its statue is in Santalune City, but if I am wrong then there would be 104 older generation pokémon in x and y)
Footage of Sylveon video
Majority of Info gotten from Serebii.net, from the x/y section and its news section
Main Pokemon X/Y website