Chat plattform development

Hi im searching for a team that would like to develop a chat platform

Some major parts of this are:
- Flutter based Web and App (Android / IOS) Backend / Frontend
- Firebase Instant massaging...
- Wordpress as CMS (or other)

80% design files for this project have been completed already.

What is needed?
- Users can register on a website or via Apps
- employees login and can give consultation
- Topic-chat
- Mail-Advisory
- Chat-Advisory
- Video Advisory
- Internal Chat between employees
- News for users
- News for employees
- Statistics
- Multilingual
- FAQ and other static pages
- Push notifications
- Settings pages for employees and user
- delete concept
- role concept


This is just an overview of main functions. What i need is a agency that is able to complete that tasks.
Please bid what you think this project will cost and give me an estimation regarding the timeframe.

Thanks in advance!