I resolved the worst of my issue by using a more powerful server.
The startup time is unworkable on a single core VPS. I was playing around with restoring backups, so skimped on the CPU. The solution for me (even for development and testing) is to use a bigger VPS.
As mentioned in my linked topic, even on my live servers (which are easily powerful enough to run the application) I get a 5 minute startup time. I will keep an eye on your planned improvements, thank you.