And yes, you can catch them without having played Black or White 1, however, I do recommend that you play one of those first, since the storyline in Black and White2 is largely based off of Black and White 1.
Note: You must have used the Memory Link to encounter N's Pokemon, except for Zorua, which is a gift.
'If you have two DS Handhelds, you can establish a link using both at the same time.
Insert Pokemon Black 2 or White 2 in one DS. Select the Memory Link option from the Unova Link Menu at the start menu. THE GAMES DO NOT HAVE TO BE THE SAME COLOR. You can use White's memories with Black 2, and Black's memories with White 2.
On the other DS, select "Download Play" from the DS Menu before starting up the game. Select the Pokemon option in the Download Play, and wait for the game to establish a link. A message will pop up on the first DS confirming the link.
If you don't have two DS Handhelds, you can establish a link over Wi-Fi. Remember, you need WEP Encryption or no Encryption when using Nintendo Wi Fi. That being said, DSi and 3DS users can set up "advanced" connections for WPA2 Encryption.
Register the first Pokemon Black or White at the Pokemon Global Link. To do so, you'll need to use the Game Sync feature at the Main Menu of the first Pokemon Black or White. Use the Game Sync ID to register the game at Pokemon Global Link after creating an account.
Next, insert Pokemon Black 2 or White 2 into the DS. Start up the game and select the Memory Link option from the Unova Link menu at the start menu. Select the Wi-Fi option and enter the same Game Sync ID. A message will pop up confirming the link. '-IGN