Without knowing the specifics, it certainly seems likely that the wrestlers could win money from the WWE. A strong argument can be made that the people who sacrificed their bodies and suffered brain damage to build the organization, for comparatively little money, deserve to be compensated for the success they contributed to.
Look, if players in the NFL can win lawsuit settlements, they why not wrestlers?
Personally, I think that even the NFL players shouldn't have been able to win. I am sure they too signed waivers about the possible injuries so that alone should have prevented them. Logically, if you are going to bang your head into other players on a regular basis, you should expect some form of damage. If you don't expect that some form of brain damage may result, you may have had limited brain activity prior to playing.
If we look at players in other sports like boxing, many of them have an obvious reduction brain activities. In boxing terms, this is what called being punch or punch drunk.
In the end, if players of other high impact sports can win lawsuits/settlements, then there is no reason to think that pro wrestlers can't.
No, former WWE wrestlers probably do not have a winnable lawsuit against the organization. Unlike NFL players who had a reason to believe that football i a safe sport to play so long as the player wears a helmet, pro wrestlers are fully aware that injuries can be very severe if a more is not performed properly.
The WWE is not a real sports organization, and the wrestlers are just actors. They chose to perform these moves, and they could have stopped any time they wanted. I don't think they can win a lawsuit now when they have already made millions and found fame from their wrestling careers.
All sports carry a level of risk for participants. I consider wrestling a very high risk sport and I'm sure the wrestlers would have signed a waiver to be involved. Typically this waiver relieves the corporation from liability, so I don't believe the lawsuit would be winnable for the former wrestlers.