What are the chances that this just turned out to be Bermite/Avalugg...The only exception is:
Burigaron (ブリガロン) — Maybe a blizzard wolf: buri (ブリ) from blizzard (burizaado) + garo (ガロ / 牙狼) meaning fanged wolf. It could also come from garou (餓狼) meaning starving wolf.
People are speculating it might be a legendary ice-type wolf based on Fenrir. We might have a legendary quartet intead of a trio this time.
I see no reason to doubt this when everything else turned out to be true. Keep in mind this rumor was floating around long before pokemon such as Pyroar and Braixen were revealed. Hell even Zygarde's katakana name is there.
Also, according to one of the leakers:
"This is the second time an NPC talks about some sort of Wolf Pokemon, more than 50 hours playing and have yet to find it."