I might not make some people happy with my choices but I did the best I could. And I can try to explain the best I can why I chose who I chose.
First off is Kyle Rayner. I know he looks young but he is now a veteran of the Green Lantern Corps and originally I wanted Ryan Reynolds for the role but since he is now Hal Jordan, I have decided to cast Sam Worthington for the role. I wanted Pine but I had another use for him (see below). I think he could fill Rayner's shoes easily.
Next up is Guy Gardner. I just immediately thought of Bradley Cooper for some reason. I thought he could pull off the cocky and humorous attitude Guy portrays. Especially when I think of the Hangover and his role in Wedding Crashers.
For Kilowog, I decided to go with Michael Clarke Duncan. I know he is an actor people like to use for multiple roles, primarily for his size, but I can just picture him as Kilowog with the deep voice of his calling people "poozers".
Now for Arisia. Now that she is back to life and second-stringer for Ion, I thought of Kaley Cucuo. Aside from the fact I think she looks pretty similar to Arisia and she is part of a number one hit sitcom, she is damn hot and I think she can manage the role nicely.
Purcell is another actor I have used several times for casting but I think he just has that superhero look to him and I think he would make a fine addition to the Corps as the battle-ready Vath Sarn.
I had a tough time with filling the role of Dr. Soranik Natu but finally I came upon the idea of using Moon Bloodgood. I think if you paint her orange and cut her hair shorter and she almost looks just like Natu.
Now for Sodam Yat/Ion. At first I wanted to use Chris Pine as Rayner and Worthington as Ion, but ultimately I decided to go with Pine the role of Ion. Mainly because he is younger than Worthington and could be an awesome Ion.
Finally is Vath's partner Isamot Kol. I like how they made two sworn enemies into best friends and I think Doug Jones can pull it off as the lizard man due to the fact he plays unusual characters very well and would look great in Kol's makeup.
Well, that's what I have. Please feel free to agree/disagree and give me any ideas you might have to improve my casting. I would whole-heartedly appreciate it.