many display models have metal wheels as they look better. If the wheels and axles are nickel plated or similar and are fitted with the correct insulating bushings for separating the + and - then they can be used.
I have tried internet searches but not much comes up, I tried to search "wiring a model locomotive" and I keep getting flooded with layout wiring tips
Unfortunately thats all I was coming up with in a search. Maybe you will have to use working parts from another motorized train to adapt to yours. You said that the seller threw in a Mabuchi motor in the deal, maybe because he did that he knows how this may work. Have you asked him/her?
No, I haven't, thanks for the suggestion, I will try it!
