One way to deny this trade as fact:
The trade DOES happen, but Aipom becomes Ambipom, Dawn is uneasy with it and trades it back to Ash! HUZZAH!!!
Eh, regardless, I can't see Dawn with Ambipom, so meh.
And that is desperatly trying to be right and not wanting to admit you was simply wrong at a speculation you did about a cartoon...
Why would Dawn feel "uneasy" with it? -_- why would they trade if that will happen? and what with all the development they got and all the building to this trade?