CasaOS is about as easy as it gets.
curl -fsSL https://get.casaos.io | sudo bash
It provides a gui front end for docker. You can install it on any debian based system (which mint is). Combine that with the portainer app and there isn't much you can't do.
Why not both?
I run CasaOS inside Proxmox
Instead of 3 small drives, why not go for 2 larger drives. You are sort of fighting 2 constraints. That case isn’t meant for 3 drives.
Also I really think you will regret the usb. You could get a pci to SATA connector and put 1 or 2 drives inside the case.
If power efficiency is important, then you will want to look for CPUs with low TDP.
I reccomend this video by Wolfgang
Or this one by hardware haven
They go into depth on low power home servers.
What’s your budget?
For a very clean professional look and future proofing I would add smurf tube behind the drywall and add a media enclosure
If you want a beautiful front end for docker containers
CasaOS/ZimaOS Cosmos-server Unbrel
Otherwise
Casaos is new. It is pretty similar to portainer. It is still a pretty frontend for debian targeted twards tinkerers.
The end goal is for ZimaOS to replace/supliment CasaOS which is intended to be a more direct competitor to Synology/QNAP software. ZimaOS will be the OS released on their ZimaCube Kickstarter
As others have mentioned there are competitors like Cosmos-server and Umbrel. CasaOS/ZimaOS has a pretty strong company behind it, so the chances it gets abandoned are low. Cosmos and Umbrel are more of a hobby of a few people that may or may not be around 5 years from now.
How much does power cost in your area? The 13400F has a TDP of 65 watts. Not bad, but not great for a system running 24/7.
Look at cosmos-server. It has a reverse proxy built in that also does rate limiting and bot prevention
Or Cloudflare tunnels.
Yes it could, however the TDP on that chip is 95 watts. Depending on where you live that will cost you at-least $10 a month in power, probably more.
However you can find HP G3 EliteDesk 800 on ebay for $90 that will run circles around that computer and take less power. Take a look at this video to see how.
CasaOS fanboy here, I've also been driving the new ZimaOS alpha. I've got to admit Cosmo-server looks pretty darn appealing.
Port forwarding will work, but it has major downsides
There are far better and safer alternatives that I would recommend over exposing a raw port to the world.