I have one newbie question. I know that Freedombox allows you to host things like Media Wiki for free, and you can run that on your own network without interference…
But are you still able to publicly host that wiki to everyone on the internet for free?
Yes, you can publicly host the wiki for everyone on the Internet for free. You own and control all the parts of the setup. Your internet connection is paid by you, the hardware belongs to you and the software, FreedomBox is completely at your control (it is an essential freedom guarenteed in the definition of free software).
If you want to configure a .com domain name which you already purchased from a registrar like Namecheap, then you will need to give your FreedomBox a public IP address and manually configure that domain to point to your FreedomBox’s public IP address.
But if you want to configure a domain name for your freedombox to make it accessible on the public internet without doing anything manually, you can register a free subdomain at example.freedombox.rocks, replaing “example” with your preferred subdomain. To learn how to do that, watch the first 3 minutes of this video: https://www.youtube.com/watch?v=37uoEbVsbNQ
When a FreedomBox user obtains a subdomain from freedombox.rocks, they would receive a different certificate for that subdomain and so this should not affect anything much for users. I don’t believe there is anything hosted on freedombox.rocks at all.