MythicMatt

You can do it basically any time after you get the first badge, as far as I can see.

Catch them at will? No, you need to use Unova Link with a completed Black or White in order to have a chance to encounter them. They aren't event pokemon either, otherwise I would've picked them up from the gallery at some point. If it's needed, I could use what I know to make a list?

Here's the deal: I recently started Black 2, and was hoping to be able to connect my flashcard Black to use Unova Link. This wasn't the case. So now, I figured why not ask here. Basically, I'd like pkm files of each of N's pokemon [preferably at the levels they were caught at] to inject into my Black save to trade onto Black 2, if at all possible.