I don't have recommendations for other articles like these; most of what I wrote came from personal experience or things I learned directly from other people working with me. I also have learned a lot from writeups by people running web services, especially when they encounter issues and/or suffer downtime or data loss. These real-world lessons can be highly enlightening, particularly if they're written in an honest way - I cannot point to any one in particular, but that's what I would look for, especially for services that run a stack similar to the one you're planning to use.
As for Python vs node, I recommend using the language you love the most, as long as the runtime you use is decently performant. node itself is blazing fast, but I would probably use it anyway if it was 10x as slow. I have no experience running Python as a web service (I've only done some local scripting with it) but I'm sure it can work perfectly well and I know of at least a couple projects which use it successfully at big scales.
I recently read a writeup by DHH about Ruby representing only 15% of the infrastructure cost of Basecamp (https://m.signalvnoise.com/only-15-of-the-basecamp-operation...). The takeaway here is that your choice of database and architecture will probably determine your costs and performance, not the programming language.
Regarding alternatives to AWS, I haven't taken the time to consider them, honestly. I use AWS very sparingly (with the exception of S3 - which has a track record that no equivalent service offers, if only for the sheer amount of time they've been at it - and SES, which I use only because I'm already using S3 and I might as well just have one cloud provider). For work with clients, they all seem to prefer embracing the dominant vendor and I don't have any powerful arguments to dissuade them from this.
At the moment I'm only responsible for a couple of services with low traffic (and handling no financial transactions nor pacemakers), so I sleep with my phone off. I've been responsible for largish infrastructures and in those cases, the quality of your sleep drastically declines. Soon and hopefully, however, I'll be running a service with a lot of user data and reliability guarantees, so I won't be able to turn off my phone anymore at night. This time, however, I'll be fully in control of all design decisions and I hope that, by systematic treatment and elimination of sources of failure, outages and emergencies should happen asymptotically less as time goes by - and with any luck, the lessons learnt can also help others that are in the same position.