Hello, How are you?
I have read your requirement and uploaded files carefully.
I am a senior Web and mobile app developer.
I have rich experience to build Hotel survey project (Android, Website, Admin site, backend).
For your project, I have a few questions.
In order to build android and web app, I would like to make API.
To use API is default method to connect server's database, but if you don't like, I'd like to use webserver (like XML).
Let's discuss more detail via private chat.
I am ready to start right now.
Hope to kindly reply,
From Peng