LAMP based booking system for a spa

We want to build an interactive, browser-based (LAMP) booking system software for a spa (or wellness retreat). We prefer to use Open Source software whenever possible. There will be five user categories, with different User Interfaces (UI): Customer, Receptionist, Manager, Therapist, System Administrator All bookings shall have a unique booking number and shall contain info about date, time, name, type of treatment, therapist name, length of treatment, room name/number plus a comment field. We believe that this should be a LAMP system, i.e. based on Linux, Apache, MySQL and PHP latest versions. The server will be cloud-based. We want to have some back-up solutions for emergency use in case of server failure or loss of internet connection. The user interface shall be web-pages designed in html5, with interactivity such that available options are dependent upon previous choices. The system is expected to be able to handle bookings for one spa-site initially, with possibilities for extension up to e.g. 10 sites. Typical number of therapists will be from 15 to 50 per site, with typically 4-8 treatments per therapist per day. First time customer registration and login on our website should be based on mobile phone number and confirmation via sms with initial password. Login via Facebook or other social media is an option we are considering. Customers shall be able to request new password via sms if old password is forgotten. We have historical booking information from the last 4 years available in Excel files. These data should be formatted appropriately and added to the new MySQL database before start-up. We will provide access to a cloud-based Linux server with Apache and MySQL for development and testing purposes, and we would like the developers to use Test Driven/Extreme Programming (XP) principles with frequent testing and extensive involvement of the system owners (Spa management) during development. Design document and supporting example file/data file will be made available on request.