Hello,
1) Is your production site or under development? If this is your production site I would suggest you to create a staging site and allow us to update the theme to the latest version there and try to fix the problem because you will need to update theme in the future and it would be better to do now than in future to avoid compatibility issue.
2) We won’t be able to add a product that uses an additional addon to the cart from the shop page. We’ll be able only to redirect to the single product page in this case.
Regards