Too late now but you may have been able to find a low mile clutch set up on from a low mileage wreck. Probably cheaper and you'd likely have the pressure plate and flywheel all together.
Final Update: I replaced the clutch friction disk as the other parts were in great shape. Put the car back together and it shifts perfectly like day 1. Mitsubishi has refused to replace the part as expected. I replaced the disk with a new OEM disk from a dealership in Florida who sells parts online at a discount.
I do realize the right way is to replace the whole clutch pack. I did not want to do it this way so that I could isolate the problem, and it was in fact the disk. I still don't know why the part failed, the new part feels good and isn't making any weird vibrations, noises, or otherwise. Must have been a weak part from a mass produced assembly. I'm happy to get it back together, and I want to make it clear I'm not upset about Mitsubishi refusing the warranty the part. I expected them to do what they did and that's just life.
Thanks for updating us on how it all went. I'm glad to hear you got it back together and things are operating properly again!