You have a point -- I don't know any of these people, and I have no idea if you're being overly cynical or not.
Is it in fact true that Blanco would have no financial incentive to continue to be sick? Doesn't he have disability coverage as well? (AMI seemed to take better care of their employees than the USPS, at least during the critical period.)
It does appear from the article that the various individuals are describing very similar symptoms and that they were surprised to discover that. But of course I don't know that they aren't in collusion; however, it would require collusion on the part of all four of these individuals, and their doctors, and their family members. I also don't think that it's necessarily fair to characterize these effects as "impossible-to-verify". The symptoms can be tested for, and malingering (to the extent of being able to fake convincingly the results of medical and psychological tests) is a skill unlikely to be found in four randomly selected individuals. (Plus, at least one of the four is likely to be honest or have an honest family member.)
What I personally believe happens is that the pending lawsuit and/or disability claim cause the sufferer to "dwell" on his injuries - because of medical exams, interrogatories, claim interviews, etc. etc., they are constantly on his mind. Doctors and claims adjusters in perfect good faith ask questions about symptoms that prompt the claimant to think about any symptoms he may have (or may not have had before he started asking himself if he did.)
In contrast, if you're not having to deal with claims or litigation, you can put it behind you and out of your mind instead of having it constantly dredged up to deal with.
While I have encountered some deliberate malingers, I think most long-term vague symptoms are caused - in all innocence - by this sort of inadvertent prompting.