>>17891576Using Pokegen, the trick is to give it the Dream World byte, but manually set its Ability to its normal Ability. So for Serperior you'd set its Ability to OVergrow, then add the Dream World byte.
Pokecheck will immediately tell you its hacked if you test it, but Bank will let it through. And then when you download it to X/Y its Ability gets auto-corrected to Contrary.
>>17891589I dunno. I bred a Sheer Force Totodile from my Pokegenned, Bank'd Feraligatr, and I was able to upload it to the GTS. I didn't try WT'ing it since I didn't want to distribute an illegit Pokemon to some unsuspecting player, but since OP received one I guess its possible.
Don't know why yours wouldn't trade. What type of trade were you trying to do?