12-22 Edit: A small patch has been applied to the servers pretty bluntly confirms these skins. The new skins now show up under their respective champions and Viktor is now in champion select but is greyed out
Artic Ops Kennen
Superb Villain Veigar
My thoughts on all this extra content being enabled is that Riot preemptively added content for the next patch early to prepare a smooth transition patch for for the holiday season that is quickly approaching. I reckon since the content is flying around anyway, Riot just decided to flip the switch and show it. Or maybe this is indicative of new patch cycle etiquette? At any rate, I must admit defeat to that Veigar skin; so fly for an evil guy.
EDIT 2: Looks like Rocketeer Tristana is visible as well! Where is out "Dark Crusader" Mordekaiser :(?