Web Development Architecture (FOCUS: Database/CouchDB)

I had few questions that might be easy for others, but that I couldn't wrap my head around.

In developing a "PRODUCTION LEVEL" full-stack web application(http://ift.tt/2ioAC9K),

1) Where do you set up your database? (when developing, I'm using apache couchdb running on my localhost, but when deployed, is cloud database(cloudant) the only solution? or am i missing something?)

2) Is it recommended to deploy my server(node.js) to either digital ocean/aws/heroku, AND set up a third party database else where? (in my case, I'm have to use either Digital Ocean/Aliyun(Chinese Web Service), but they don't seem to have a database package that comes with couchDB) - What is the practical solution for production level application?

3) If cloud database is the practical solution, What Do I do if there is no database storage center for CouchDB located in China? is there a cloud database storage that universally saves all noSQL data regardless of your type of DB? (mongoDB, couchDB, etc.,)

4) AWS/Heroku provides add-ons where you can connect cloud database to my application, does this make the speed of my application faster? For Digital Ocean, it shows article about setting up CouchDB with their service, but does that mean that database will be available for my users to access? or is that just for development purposes

5) Where and How does "Docker" come in to play to help in my situation?

Sincerely,