I use nylon strings on one of my guitars and slide technique is no prob with them. I have no experience with a banjo but it might be worth a try. Perhaps it works.
The Lonely Bull was originally played on an ordinary (electric-)guitar but it sounds a bit like a slide guitar because there is a lot of reverberation. That's an effect you can't copy with an acoustic string instrument, I'm afraid.
And I'm currently listening to The Lonely Bull =) Haven't heard that one in decades and totally forgotten about it. It's rather an earworm!
Btw, do you know the
Wild Cat Blues? That one might sound really great played on a banjo. Even one with nylon strings