Nice, sounds like a good lab. On the static IP and DNS problem: you can skip your ISP completely by hosting on a shared "tilde" server instead of at home.
I checked tilde.team's wiki just now. It serves Gemini from ~/public_gemini (CGI works too), Gopher from ~/public_gopher, and it has a Finger page with a .plan guide. So all three things on your list can live in one free shell account, and the netbook stays your editing machine. SDF is the older option that also does Gopher.
If you only want a Gemini capsule with no shell, flounder.online is a free web front end for Gemini capsules.
If you'd rather keep it at home later, dynamic DNS covers a changing IP, but it won't help if your ISP puts you behind CGNAT. In that case a tilde or a cheap VPS is the easier way.
https://tilde.team/wiki/gemini
https://tilde.team/wiki/finger
