I figured it out. At first I thought maybe it was something with the router, since I had previously turned off all the services we weren't using. Turns out it was just me being dumb, hence turning it on haha!
I was trying to find the host on the same machine that the server was running on, i.e. running the server and a client on the same g3. This worked just fine before, using AppleTalk, but I guess it doesn't work when switched to tcp/ip. I tried it on a different computer, and abracadabra, the host files show up.
The next project is convincing the boss we need a "separate" machine to run the server!