Settings and UI alterations to already working opensource android app

We are embarking on a project that will involve converting an existing opensource Android application to a closed source, paid by subscription Android application. We have permission from the original owner of the open-source application to proceed with this project. On the whole, we are not changing the core functionality of the application and how it works. We require the application to have the following changes made. Please check each one carefully and ensure you are capable of delivering what we require as these are core requirements for our application. I believe most changes below are very straight forward. 1. UI Facelift of application. The same settings and functionality will be present from the existing application, we just want to implement a nicer, more user-friendly UI app home screen. We will assist with providing a wireframe or mockup ([login to view URL] of what we need the app screen to look like, and where all the remaining settings and options should be seen. A couple of the existing slider settings will be moved to the home screen for example. App will be tested to ensure all functions work at this point as intended. 2. Notifications. We need the developer (you!) to add notification functionality so that the app will send an email to a user-entered address if the service/app has been stopped, uninstalled, etc, etc. Alternatively, the developer will come up with a way notifications can be sent to a partnering app that is synced via qr code, etc etc. 3. Implement a way that the app cannot easily be closed (perhaps implement an overlay function, etc). This will need to be tested. The objective here is to make it difficult for the user to close the app. 4. Add subscription functionality. The app will be sold on the Google Play Store for a monthly subscription, NOT a once-off fee. The app should only work for paying subscribers. If a user cancels the subscription, the app should stop working. This is to be tested by the developer. 5. Change code sufficiently so that the new application is seen as unique by Google and we are not seen to be simply cloning the existing application. The original developer of the application has mentioned this will need to be done to ensure google will not decline the application being added to the app store. 6. Set defaults for existing available settings. We have configured the existing application with settings that we wish to make the default for the new application. Screenshots will be provided of existing settings to make the default for new app. 7. Hide some GUI elements as we do not want them to be modified in this new version of the application. 8. Remove all references to existing developers throughout the application (find/replace), but credit original developer in the "About" menu option. 9. Testing against various Android devices via the SDK emulator. We expect this to work on at least the previous 4 versions of Android, and across many devices. 10. Assist and guide us through creating a Google Play account and officially listing the application for sale. We expect to communicate with your team via WhatsApp. This is a very important app for us as so we would like tailored responses please, not just automated responses. Looking forward to working with one of you.