Oh and don't forget that now maybe you make everything work, but in two years time your setup won't be reproducible, because chances are the original images are not available any more, they got deleted from Docker Hub some months after you used them. Yeah, you should update them anyway for security... but the setup itself is not reproducible, and being forced to use the latest version of something, with the new idiosyncrasies it might bring, is not a nice situation to be in when you just want to hurry up and resolve your downtime.
So I guess that's one more thing to worry about it seems, maintaining your own images repository!
Maybe, but when the original docker image is no longer available on docker hub, chances are there will be something better and even easier to setup. And with docker you don't care about installing / uninstalling apps and figuring out where that obscure setting was hidden - all you need is just a stock distro and a bunch of docker-compose.yml files, plus some mounted directories with the actual data.
But a lot of those unofficial docker images are of unknown quality and could easily contain trojans. It's completely different from installing a package from your distro.
On the plus side, the Dockerfile and the repo with the scripts used to build a container is usually available. If you don't trust it, read through the source and rebuild it. Or just stick to official containers, no matter how terrible they are.
Even if so you're still spending say 50% of the original time investment every year or so just maintaining it. Unfortunately your options seem to be "set up once then never touch it again" or "update everything regularly and be at the mercy of everything changing and breaking at random times".
I mean, you should always have a backup of your dependencies (up to reason).
I develop mobile applications, and use SonarType's Nexus repository storage as my primary dependency resolver. Everytime I fetch a new dependency it gets cached.
A monthly script then takes care of clearing out any cached dependencies which are not listed in any tagged version of my applications.
So I guess that's one more thing to worry about it seems, maintaining your own images repository!