Ralph Geb, Malcolm Wallace's high school friend. The photos in the link below of Geb are taken approx 25 years before the MC Oswald imposter.
Regarding Ralph Geb in my opinion he was never intended to look like Oswald merely create paper trail with accomplices in MC as par of the framing of Oswald.
The CIA never intended issuing the embassy photographs of the MC mystery man because they knew it wasn't Oswald. However, the FBI sent them under pressure from the Ambassador. Released files state how regretful the CIA were that the photos had been entered into the chain of evidence by the FBI whilst under pressure.
Oswald was in MC but had been sent to deliver toxins to a contact to kill Castro. However, this too was part of the plan to frame Oswald and actioned by David Atlee Philips aka Maurice Bishop.
Hoover was quick to report to LBJ that there was another Oswald imposter in MC to push the focus towards the CIA whom he hated. Hoover couldn't do anything but cover things up as Oswald was taken off the FBI watch list just before the assassination when Hoover learned fully of the plot. Also Angleton had blackmailed Hoover and Hoover great friends with LBJ would have been retired if JFK remained in power.
http://truth1.org/images/duble/zz88.jpg