Firebase - Mobile app text messaging system

I want to build a simple text based messaging system with some unique features into it. In this we don't need any image or video sharing This is a very simple app - firebase makes it easy for you Technologies: 1) Google Firebase - use firebase features as much as possible 2) Android, iOS and Webapp 3) Prefer Hybrid app - if there is any issue then we can go with Native 4) Google Maps Key Features: 1) Create/Modify Groups - can subscribe, add particiants (not needed for web app). Group members can be in contact list or can be out of contact list 2) Watch a Group 3) Notify Group - Notify only if the person is watching a group. While whatsapp does for everyone 4) Only Text messages less than 100 chars 5) Send message - only one person who is admin can send message - Need to process the content of the text message into different meaning - like if it is in certain format of contact then detect as contact. At the moment I will give only one detection rule. 6) Ad intergration 7) In app purchase - for Ad free option 8) Need to search feature - group and participants in the group 9) Need Settings - to set password for web, to set email id , web authentication 10) Need sharing option about app to Social media - just for advertisement I am not planning to use any server other than firebase. If required please let me know. HTML5, javascript and hybrid app development skills should be enough. If anything required in server, then I prefer you to use java for server side coding. Please note that most of your work is already simplified by Firebase, so I want you to be a firebase expert. Need to sign NDA that you will not use this code base for some other product or client other than us