If the printer has an ip address, have you tried discovering it over the network? It's easier all around if you give the printer a static ip address and then ping it to make sure it's on the network. Once it is, I think you should be able to discover it like any other networked printer.
If you don't have the HPLIP GUI (hp-toolbox) installed, you can use hp-setup. If that doesn't find it, you can try passing the ip address of the printer to hp-setup with
hp-setup -i [ip address]
On one of my machines, I did have to pass the printer ip to hp-setup. On the others, hplip has been able to find it without additional help.
My printer is wired, so I can't test this and I may be whistling in the dark.