“Take this with a grain of salt”
The new games will have a full connection with your Nintendo Network User Id/Name. This will also be one of the first mainline Pokémon games to have multiple save files, with (3 Available slots).
Even though the in game name and trainer ID will be different, your Nintendo Network User ID/Name will prevent you from trading back to yourself on GTS while on different files. Basically it’ll prevent you from self trading while on the same version of the game. But having 1 copy of Sword and 1 copy of trading to yourself under the same Nintendo Network ID is okay.

Wonder trade will remain intact the same and anonymous. Sadly this is not what the direct is about. E3 will brush over this topic