Thanks for the thoughts on Waldman.
You are correct about the plates. I worked in newspapers for many years when it was all hot metal.
Alan Class stated that he received "photostats" of the comics from Marvel, from which he had plates made. (There is an interview with Mr. Class on the same page, but you might not want to watch, given the FF #1 story). However, your comment, "If those were authorized foreign reprints licensed by Marvel" does reflect certain theories which were doing the rounds some years ago. Reading his various titles, you'll come across material from Marvel, Archie Radio Comics, ACG, Charlton, King and some others.
According to the interview, he used Transworld Features Syndicate, who represented Marvel, to facilitate his reprint books.