This solved it. Thank you!
I have the GTK2 theme working now.
Now I can clear up the plugs and sort the desktop lanucher and icons out and offer the final yaml file up to the devs.
Quick question, just in case you know, though I will research if not:
Some of the packages that I added to transgui's stage_packages section are now duplicated in the stage_packages section for GTK2. Do I need them in both sections, or can I remove them from the transgui section if the GTK2 section is providing them?