Flutter UI for CMS, approval, ecom and categories of content, end user and site creators apps

Project to take a performent and great UI in flutter for a new site that will be in one language (English with a seperate install for one more later) Need categories for content, admin, editor and content creator sections (or a seperate app if that is easier) with 2 people to approve content before it goes live. Back end will be developeed by another team, need someone who can work with them to make the front end UI and talk to the back end. Will work with a great designed who will provide design and look and feel in HTML + CSS, need to follow that to create the UI Writer adds, editor approves before its live on the website 2-3 Merchant ids for differnt market sections with initiall 1 Payment gateway, but design to add 2 more in next 6-7 months Launch date - you suggest after discussion To include developer testing and deployment Site will be in 1 language for now and for 1 geographic region One Shipper API also has to be integrated with the site along with PG. Can show u some mock ups of the site to serious bidders