Some of the highlights in the video are that Bruce confirms multiple colored Lanterns will show up in first season of the series. He goes on to say that Kilowog even says at one point, "Geesh, how many colored Lanterns are there?"
Bruce also said that Hal wasn't the first choice by DC to be featured in the series. They wanted him to go with Kyle Rayner. He was reluctant to hire Josh Keaton for the role since he had voice many other superheroes in the past, but his audition won him over.
The series won't be telling the origin tale, it will pickup from Hal being Green Lantern for at least a few years. And don't expect Hal at any point to become Parallax.
I'll be posting a review of the footage that I saw soon. I'll briefly say that as someone who hated the recent movie with Ryan Reynolds, I was incredibly impressed with the animated series. Just goes to show you that DC is still one of the best at adapting comics to an animation format.