Liam here from Shopify - thank you for your question :)
Great to see you are looking to have the correct variants available to your customers, so let's see how we could integrate this onto your theme. As you have seen the link product options customisation is not compatible with the Debut theme but it could be possible to get this functionality from an app like Product Options. This app will allow you to apply Conditional Logic to variants so that you can show or hide options based on the selection of previous options. That way the product pages will update secondary menus in line with the current selection, to avoid showing unavailable combinations of options when a customer is choosing from multiple menus.
Hope this helps Jo, if you have any other questions, just let me know!