Is Battlecast canon or does it take place in an alt reality?
Because of the spells seems canon since they expand quite a lot on the Skylanders' powers(and they wouldn't hire Hearthstone artists for nothing), but it's on another dimension opened by a rift(which is just an excuse for card game,because "conventional forms of battle aren't allowed"), so it's just that it doesn't affect anything other than lore.
No new villains,since it's half reusing models from Battlegrounds,half using the villains because they have their own spellcards.
The Academy is crazy slow too,though, so it's weird that they didn't see the giant creaking airship right under them for 15 days if Kaos started chasing them right away. So much for security.