This doesn't answer all your questions, but there is an example automated install of WordPress with the Distelli SaaS platform. (The platform offers free accounts.)
Once this is setup, you can deploy to any environment very easily. This is flexible enough that you can easily change the db name|password|user|etc. I've imagined some changes to meet your use case where you can specify these per environment.
This doesn't answer all your questions, but there is an example automated install of WordPress with the Distelli SaaS platform. (The platform offers free accounts.)
Check out my blog here:
https://www.distelli.com/blog/deploy-wordpress-to-ubuntu
Once this is setup, you can deploy to any environment very easily. This is flexible enough that you can easily change the db name|password|user|etc. I've imagined some changes to meet your use case where you can specify these per environment.
I can answer questions if you have any.
Good Luck and I hope to hear back. -B