Hi,
Hope you doing great
I reviewed your post & found that apps in Shopify product options or product customizer we cannot change the code of apps as they are hosted on App developers hosting only app developer can change it, as you see when you select the apps they do not run in Shopify url they redirect to another url which belongs to app developer then come back to Shopify url. So in that case you need to contact app developer or we can create app from native but you need to provide developer account of Shopify and hosting where we do the code.
Please let me know your inputs on this. Add me on skype: cis. brenda or brenda.cis40 ( a t ) g m a I l (d o t ) c o m
Regards
Brenda