Yes, you are correct. There is a "lineage" that goes through Mr. Wong. Of course, if we count the "re-makes" that were several of the later Fox Chan films, we could say that there is something of a family tree, there, too. Two other Charlie Chan films that have roots extending elsewhere. One is "Charlie Chan in City in Darkness." The credits for this film indicate it to have been "Based on a play by Gina Kaus and Ladislaus Foder." There is also "The Feathered Serpent" which was based on the 1937 movie, "The Riders of the Whistling Skull." (Interestingly, Robert Livingston was in "Riders" and later appeared as John Stanley in the Charlie Chan version more than a decade later!)
I have Riders of the Whistling Skull... which is one of the better Three Mesquiteers films... so watching Feathered Serpent here soon should be fun.
Best for Christmas... we're getting nicely snowed in here now.
Len