Green Lantern the Animated Series/WMG

The Manhunters will resurface and take over as the Big Bads.
Something tells this troper that the way the Manhunters were brought up in the series was for more than just to detail the Red Lanterns' back story and show what an Old Shame they are for the Guardians. Perhaps they'll rise up to try stealing Oa's power, as they did in the DCAU, by taking advantage of the technicolor war.
 * They may be Big Bad Ensemble with the Red Lantern Corps.

Ganthet will become more helpful with the crew.
He may join them as The Mentor. Or as a Spirit Advisor/The Obi-Wan, he's not dead but he'll be involved in something offscreen.
 * As awesome as the theory is, it's likely not to be. Ganthet's VA passed away by the time "Regime Change" was in post. So they'd need to find The Other Ganthet pretty soon. However, I suppose there could be a background role, if the Blue lanterns show up. With a "Ganthet found the prototype and created more. He recruited us." kind of line.

Razer will get rid of his Red Lantern ring and become a Blue Lantern.
It won't happen until one of the last episodes of the season, but it will come in time to help defeat the Red Lantern invasion.
 * And he'll use the oath Aya wrote him. Think about it: "Can lead your soul away from dread/and heal the deepest wounds of hate./Let no one else control your fate." Its an oath of healing and hope. It has the added bonus of explaining why it couldn't recharge his red lantern ring: the blue light of hope shuts down the red light of hate so of course it can't recharge it.
 * Jossed for this season, but we'll see later on.

Ilana will become a Black Lantern.
She died such an early, untimely death. It's not too unlikely that it could happen. It will, however, leave Razer even more of a Heartbroken Badass.
 * Doubtful, given that Aya borrowed her face and is usually partnered with Razer, forcing him to at least pretend to deal with his issues. Bringing Ilana back would cause a lot of overlap in terms of how they fit into the story.
 * It would make for an interesting Love Triangle though.
 * As of "Invasion", Aya's been, so we may get a storyline like this after all.
 * In "Homecoming", Aya's been, so such a storyline will likely have.

Razer's going to have to come to better terms with his apparent
I predict that some of his care for aya is genuine, but that part of the apparent Love that allowed him to  might just be him remembering Ilana since he now sees her face every day. This is going to lead to some very interesting Pinocchio Syndrome moments, as it's too obvious an opportunity to readdress Aya's status as a living computer rather than an actual being. (This might also be an interesting time to ask the question whether Aya can ever be an official Green Lantern)

Mogo's male prisoner will become .
Now that we know that it seems that he would be a great candidate, and he does have the physical resemblance.

Razer will try to create a Good Counterpart splinter group of the Red Lantern group.
Under suggestion by Hal and Kilowog. Having other lantern groups as their ally will be quite useful, and the fact a Red Lantern's motives have a potential for good does give the potential for heroics(or at least lawful antiheroics.

We'll see Parallax at some point
Bonus points if Clancy Brown reprises his role.

We will get our first appearance of Sinestro in the season 2 premiere
Come on! It's like an unspoken rule that the Arch Enemy of all Green Lanterns eventually has to make an appearance in all animated appearances. I predict we'll get part of the season with Sinestro as a Green Lantern, and part of it with his famous foundation of the sinestro Corps. (Bonus points for the Sinestro Corps War being an actual storyline, bringing up the violence clause Lanterns use to have)

We'll see Red Lantern Aya at some point.
Not that she'll be recruited by them, but rather she'll end up getting charged by Red Lantern energy and turn red for an episode. Most likely, there will be some situation which forces the crew to jump-start the Interceptor with Razer's battery.