That is all you really need unless you are looking to have 1000s of people connect to it.
That was mostly the idea, since it'd be an open server, let as many people as I could connect to it.
And besides, if I'm also considering whether I could run 2 at once (public and private), I'm guessing that if it's possible, it'd need quite some resources
You'd need 2 computer to have public and private server, unless you have experience with virtualization/container tools (VirtualBox, Docker, etc.) and computer with decent RAM size.