— As the leader of Pelargir, Kemen will be given one of the nine and will eventually become the Witch-King
— Theo will eventually become leader of Pelargir after Kemen is run off by the Ents. He becomes the King of the Dead.
— I'm torn between whether the Dark Wizard is Saruman (which doesn't make any sense but seems hinted at) or one of the Blues. Especially now that we know the Stranger is Gandalf.
— Nori and Poppy will lead the Harfoots and the Stoors west. The Stoors settle along the Great River and are Gollum's ancestors. Nori leads the Harfoots to found the Shire.
— Tom Bombadil will make an appearance again but this time with Goldberry in the Old Forest
— The Entwives' disappearance will be addressed in the next 1-2 seasons
— The Balrog won't factor in until at least the end of next season while the Dwarves deal with internal strife.
— The infighting with Durin's family will lead to Erebor's founding

On a side note, I really liked season 2, but I did not like the new Adar actor. I liked the original much better.