Greetings,
I hope you'll be doing great. Please have a look on my recent reviews on the profile. All of them are related to shopify projects, so, u should be sure you are in expert hands.
Let get back to current project. Most of the apps are standalone functionalities and we can't interacy with app's code. As you mentioned in project description about template, so, i believe it is possible to achieve desired results. Please share the details of website, so, i can inspect it deeply.
Please also take into account proposed budget is very low and it isn't possible to work in that budget. I hope you won't mind the quoted figure. Please feel free to get in-touch and discuss in detail.
Regards,
Zeeshan