Hi, my name is Matt S Rinc and I can help you as a software developer for 20 years.
Would you please clarify what you have and/or require?
1. A web application which can run on phones (web browsers) and for example on Linux (to be embedded in your "box" hardware with display etc)?
2. Do you need native mobile phone apps e.g. for iPhone/iPad and Android that would be uploaded to AppStore and Google Play?
Actually I would create an application with Kivy, a software framework that can generate applications for Windows, Mac, Linux and iPhone/iPad and Android devices.
But please really I need more specific details. Milestones would be:
1st, draft application, 50%.
2nd, final application, several platforms, graphics enhanced, 50%.
Regards,
Matt