GZDoom + supporting .WAD files: ~130MB installed.
Ultimate Doom Builder: ~35MB installed.
Foobar2000 + .mod file support: ~13MB installed.
OpenMPT: ~21MB installed.
Okular: 230MB installed.
Fill the rest up with community maps/mods, tracker files and ebooks.
Even if it isn’t changing IP, you still want it in your DHCP table so that IP doesn’t accidentally get assigned to something else. It’s unlikely on a small network but it can happen.