Create a Classified project with (iOS + Android + Web + backend admin panel) -- 2

We’re trying to develop a system that includes frontend website, with customized CMS backend that integrates the data with Android and IOS app. The system is intended to be used as a portal for business opportunities and classified. Please review the requirement very carefully and share your detailed proposal. I am ideally looking for a long term relationship with the developer as I need to upgrade and customize features of this project right after the beta phase. This is going to be a customized classified portal. That would buy and sell businesses, search buyer profiles, search seller profiles and search business listing on specific column basis. Please note: we're looking for 4 types of profiles on the portal with search features on profiles. 1. Investor / incubator - Classified buyer - 2. startup / business / founder - Classified buyer - 3. Founder / business owner - Classified seller - 4. Business consultant - selling business services - Classified Seller - 5. Business listing - classified adds Sellers profiles (3 & 4) should be able to post a listing using the web / mobile apps. Superadmin / backend should be able to add / edit / update listing. Upsell / upgrade classified add and all 4 types of accounts. All 5 items should be searchable (4 types of profiles + listing) in their specific categories. I am ideally looking for this add in mobile Native language with a backend cms made on the customized extensible code. I am looking for an experienced developer / team who can deliver this project within a short timeframe.