I am familiar with the two recent releases that you mention. Hopefully, all Chan titles will be released, eventually, but I am in the dark, there. You may look at the Web site of the publisher, and see if any information can be found there. Also, a trip to Amazon.com could offer a clue or two.
Again, I know what you know at this point, but will check into it myself, as well.
A trip over to Amazon.com proved fruitful! The answer to your original question seems to be yes. On May 9, "Behind That Curtain" was released, thus indicating that the rest of the stories will be available at some point fairly soon.
For those not familiar with the current releases of the Earl Derr Biggers Charlie Chan stories, I can tell you that these are of fine quality, and each has a very handsome cover (dust jacket) illustration.
