New Pokemon that consist of Genesect and Meloetta(Keldeo to be released in the US soon). There are also new forms in BW2 which consist of Theiran Tornadus, Landorus, and Thundurus, Black and White Kyurem, and Resolution Keldeo.
http://www.serebii.net/black2white2/forms.shtml
No, the BW2 pokedex consists of all unova pokemon plus many from past generations.
