From Comic Con reports on Twitter and elsewhere. Quotes used when I quote something exactly:



- Book 2 is "Spirits" and starts six months after Book 1.



- To the Southern Water Tribe, Team Avatar will go.



- "Book 2 will explore the Spirit World and how the "Avatar" lineage began. Korra will travel into the spirit world and Konietzko hints that there may be episodes later in the season dedicated to exploring the bigger landscape of the Spirit World History of both Spirit World and Avatar will be explored."



- "We see Korra encounter a spiny spirit in the Southern Water Tribe. He's spiny and wicked, like one of Miyazaki's darker creations. The creature moves with lightning speed, pinning Korra to ice. She enters Avatar State to whip fire and water at the beast, but he tunnels underground and escapes."



- "Korra will have new threads inspired by Mandarin, asymmetrical fashion. Mako and Bolin will get big, fluffy coats for the frozen tundra that maintain their color coordination"



- Asami takes over Future Industries



- Bumi and Kya as regular characters (Kya is apparently a hippie.)



-Korra's uncle is named Unarock (don't know about the spelling)



- Pro Bending returns, but with only Bolin playing



- "Korra airball races Jinora & uses Avatar state to beat her! Tenzin's pissed" - "The Avatar State is not to be used as a booster rocket!"



- Mako becomes a cop and is fond of tossing out one-liners to criminals ("Looks like someone had car trouble.")