Unfortunately, according to Paul Ryan, the dude in charge of Pokeshopper and all merchandise, he claims that a new Eeveelution seems unlikely. There is only one new mystery slot on Takara Tomy (Takara Tomy is very popular for figurines), with the slot almost certainly being tor Zeraora. If there was going to be a new Eeveelution, the Takara Tomy site would have two mystery slots instead, since they'd definitely want to market a potential Eeveelution.
However, what's interesting is that, even if there chances for a new Eeveelution look low, that Banpresto mystery next to Eevee in the link certainly guarantees something new for sure for Eevee. So if it's not going to be an evolution, could it possibly be a new game mechanic?