Hybrid mobile phone app for wordpress website

The job involves a Wordpress website which has a custom plugin which I have developed which allows users to create a profile and fill in a calendar with dates when they can and can not work. Employers can then search the users and filter results by users that are available to work between certain dates, job title, country, and whether they have marked them as a ‘favourite’ or not. This is in place already and my client requires a mobile app that will hook into the website and provide some of the same functionality. So we require a Hybrid Mobile Phone app that will work on iPhone, Android, Windows, and possibly Blackberry. The requirements are. 1. App authorisation process with login credentials checked via the existing website. Landing page to select ‘user’ or ‘employer’. 2. Users can edit a calendar with three statuses , can work, can’t work, maybe Users can send a link to their calendar/profile by email. This is to offer the user a dropdown of email addresses from their phones contacts 3. Employers can search for users using the same filters that are available on the current website: by dates that they can work, job title, country, and by ‘favourites’ they will get a list of results and be able to open a users profile page and view their calendar. 4. Employers can mark users as ‘favourites’ and un-favourite them 5. Employers will be able to see a list view or all their ‘favourites’ in a grid format that can be scrolled left/right showing the dates that each user can or can not work. *** To be successful *** I require a realistic estimate of the number of work hours that you think it would take for you to create an app based on the specifications above. You need to specify what you will use to create the app. For example Ionic/Phonegap and SDKs and what you will include in your full development environment such as NodeJS, Bower, Grunt, Gulp etc You will need to supply a couple of examples of previous work. Thanks. Rich Hancock