I don't have 2 nintendo 3DS, or 2 game cards, or any friend to trade. The Pokemon I get from GTS won't have my OT. Where can I find someone to trade and trade back? Or is there another way to get Milotic with my OT?
Your best chance would be to breed your own Feebas and trade it with someone online and have them give it back to you. The OT is permanent, so even if you trade it away it'll always have your OT on it.