Very interesting, Rush. Fox Films/20th Century Fox owns rights to their own films, but stops making any further releases. Then Toler buys the "Character" rights from Eleanor Biggers Cole, probably like you say with a handshake agreement from Monogram Studios they'd continue. How much he paid is anyone's guess. However, he either paid her a good sum or Eleanor might have gotten a piece of the action in the agreement. What is also interesting (to me) is that 20th Century Fox now again own the rights to the character. So sometime after Toler's death they must have purchased them from his estate.
Yes. I am guessing that 20th Century-Fox bought back the character rights around 1968 when there was something of a Charlie Chan revival. Fox stood to make a good income as their Chan movies were released for television airings. If seems that Warner Brothers was in the mix, as well! We see that the re-released publicity stills for the films At that time bear the name and logo for “Warner Brothers/ 7 Arts.” This might also explain why Warner somehow holds the rights to “The Black Camel.” This affected the Fox DVD release of that movie in the early 2000s.