Actually, Lani does all of Crais' lines (in ADR) first, then he does Pilots'. And it's all his own voice... no special effects there. Crais' voice is just a bit deeper than Lani's actual voice, but he really works it to get Pilot's voice all high-pitched and soft, so it starts to bother his throat after a while. He even has to scream differently for each character.
And, I agree, his work on Pilot's voice is amazing. I can just imagine all the cool voices he's capable of doing.
At the con last year, Lani took the audience through a voice warm-up and a scream practice. He had one side of the room at a time do what he did, beginning with the warm-up, then going through the motivation for the scream, then the scream itself. It was a real hoot.
See the pic below for an image of that. This one was the "IP1,Talyn's been blinded" scream.
Thanks for starting the topic, Shel! You keep disappearing after you start these great threads, though. We still want you input.