>>17955924>which is accomplished differently depending on if you're using Diamond/Pearl, Platinum, or HeartGold/SoulSilver.For the record, Googling around can get you a precompleted save if you don't want to run through the 4th gen game for this. You could also just use a walk through walls cheat to get past the road blocks to them, since you'd be doing that on an emulator too.
You don't necessarily have to connect to wi-fi with Desmume either, you could just as easily upload them to Pokécheck and download them onto Black 2. I can't say for certain, but there may even be a way to upload them straight from Emerald.