You should NEVER edit any of the files inthe template_default folder.. You would instead create an OVERRIDE file..
Glad you figured this all out, but any further questions on product page layout should be posted in a more appropriate thread.. I know you don't think that your questions are unrelated to support for the hideCategories support thread, but they really are.. You confirmed the add-on worked as it should. ALL of your page product layout questions (the order in which items appear on the product page) are OFF TOPIC for this support thread.. Therefore the layout of the product pages is a separate topic that has nothing to do with support/troubleshooting this add-on and going forward should be posted in a more appropriate place on the forum....