Sheridan Peterson is, by his own admission, a compelling DBC candidate based on skills and experience. His eyes, however, are the bluest you will ever see. He has no criminal record (other than a bogus arrest while doing civil rights work in the South) and abhors violence. When Sheridan was broke he'd always find a job, not resort to crime. I can't see him threatening to blow up an innocent crew just to get money. He has a very distinctive way of speaking which is obvious in the Case Closed interview. In his 90s, he is mentally sharp, articulate, very up to date on current affairs, fit and good looking. He would solo skydive today if any DZ would allow it. He has plenty of grudges relating to horrible atrocities he witnessed during his time in Nam. He worked at Boeing in Tech Documents, was a Smoke Jumper, Expert (D License) skydiver and USPA rated instructor. He also knew USFS Smoke Jumpers working for Air America in Nam. Could he be DB Cooper? Sure, but he'd have to have been wearing brown contacts. His eyes aren't just blue, they are piercing blue. A witness would be very unlikely to have seen those eyes and called them brown.
377