I think Pichu will be like Pikachu in Yellow, trade it over to DPt and it'll be normal, and you can evolve it, but when you trade it back, it won't be Notch-eared anymore, due to evolving.
everybody here should know that you have to get the movie arceus and the notched ear pichu in D/P/Pt the events will be b4 the games come out in america{L}