Laugh all the way to the bank, most likely.
This is sad but common. Stock options in a company that hasn't gone public should be treated as a lottery ticket: It's nice if they turn out to be worth something, but their most likely value is $0.
Wouldn't it benefit the founders more in the long term to make good with their employees for the benefit of working with them in future endeavours? I guess when you're getting a 7 figure payout, it doesn't matter because you can just retire?
If you truly believe they did something nefarious to stiff the guys at the bottom of the cap structure, and it was a fairly sizable chunk of money, you (solo, not with your ex-coworkers) could take whatever documents you've got and briefly consult with a lawyer. Just an idea from someone who has never been in your situation. I've hired a lawyer (something which I am not) to bite back at people who tried to screw me a couple of times. May be futile in your situation, IDK. You have to figure out if it's really your money they're paying out, and whether there's a basis to argue that the directors violated a fiduciary duty to you.