The only complex part of the hardware is the HP cartridge controller, and you have at least part of the work here: https://hackaday.io/project/176931-hp-printer-cartridge-control-module/details

Was “Yakety sax” playing in the background when they said that?

Brother HL 2030, and the scanner is a Mustek 1248UB, both chosen for their Linux compatibility at the time. And most likely both discontinued.