That's great news!
First I tried this (thanks @JMichaelTX for reminding me of VBA):
But as it turned out, the text boxes walked like a text box, quacked like a text box ... but were some something different. Perhaps MS Word objects? Anyway, this surprising use of BBEdit gives hope.
One strange thing: my View > Wrap command is greyed out. How did you manage to have your text wrapped?
Next step for me will be: Save the 'drawing' as an XML file. Modify (translate) it and put it back in BBEdit. If that works too, I'll try to build (get) an AppleScript to save all files drawing*.xml as separate XML files. And one that puts everything back after modification. But first let me do this initial test (later today).
Thanks the both of you for your answers!