Thank you for your thoughtful response.
Firstly, You are absolutely correct when you say that we mainly faced issue with NoSQL rather than firebase. But as we only used firebase as our NoSQL data source i titled the article like this :P
Secondly, I still think inconsistency of data can be mitigated by proper tooling and testing but as a small team of 5-20 developers we still feel that SQL is helping us to achieve more productivity as we have to worry less.
One big issue that i feel about firebase is that you can't control what you are adding to firebase document. absolutely anything can be added to a document. It's a plus at the beginning but after some time it becomes risky. As of now i don't know any tool to put a safety guard on database level. But database level protection in SQL is helping us a lot. This way if someone is unaware of any bug or malformed data it's easy to identify before pushing it to production.
About the services you suggested here. I have little idea about most of them as of now. I will surely check them out :D .