User blog comment:Energy X/Pokémon: Orange and Purple/@comment-5232302-20160806172003/@comment-5232302-20160806220348

As a recap, see this comment. While the trainer that owned the Whimsicott may have been originally been from the Unova region, this is possible for the Trainer owning the Whimsicott before she came to the Provo region or in this case, she came from the Unova region.