Why theme-level beats page-level
A Shopify catalogue changes constantly. Any AEO work implemented page by page decays the moment someone adds a product, so the only durable place to put it is the theme. A schema section attached to the product template applies to every product that will ever exist, including the ones added after the engagement ends.
The four changes
Start with FAQPage schema, because it is the one an answer engine can use directly. Then the direct-answer paragraph, which costs nothing but a rewrite. Then the glossary, which is slower but compounds. Crawler access is last only because it takes ten minutes — check it first if you have never looked.
What to measure
Fix a query set at the start and re-run it monthly. Model responses move on their own, so a baseline you did not record is a baseline you cannot claim credit against.
Common mistakes
The most expensive one is marking up FAQs that do not appear on the page. Schema that contradicts visible content is a trust signal in reverse, and both search and answer systems treat it that way.