For my Brother QL-570 mentioned above, I've decided to go with reliable but less atrractive route. I created a file in P-Touch editor and wrote an AppleScript to open that file from within a FileMaker script. In that FileMaker script, there is a script step that copies the required information for the label, along with commas and carriage returns, into the Clipboard. Once that data is in the clipboard, the AppleScript is executed to open that P-Touch Editor file. I then 1) click in the text box 2) paste from the Clipboard and then 3) Select Print. Of course, I created a button in FileMaker for the appropriate layouts. So after, that there are only 2 or three more user-required executions to do it, but it works. Not as simple as FileMkaer would be expected to do, but oh well.
I'm seriously thinking of getting rid of this label and go with the Dynamo.