Create chatbot for my scenario and fitting my requirements

We need chatbot working under these scenarios [login to view URL] . So it will be combination of decision tree and intelligent chatbot. Please, answer the following questions in your applications or cover letters: 1. Will the architecture of your solution be flexible enough to let us add our own intent recognition logic available through API endpoint (or smth 3rd party like DialogFlow etc)? 2. How much money and time will it take to create the chatbot fitting our requirements? 3. Will I get all sources of the chatbot? 4. Can the chatbot be create as standalone solution, however afterwards easily transferred to Fb Messenger? 5. What platform (programming environment, 3rd party solutions etc) will be used to create the chatbot for my case? 6. Where can I try chatbots (or their demos) you have already created?