Just saw the question... I know of several different ways to dup items although I have never tried to dup the wabbajack

I'll go try the different ways right now, give me about 30 minutes and I'll let you know if any way worked

OMG... two Wabbajacks should be illegal, way too much fun lmao... oh by the way...

SUCCESS!!!

I managed to successfully dup the wabbajack... without mods... and with the Skyrim Unofficial Patch installed... this is the exact method I used...

Grabbed wabbajck from storage

Fast travelled to Riverwood and got Fandel as a follower

Fast travelled to Markarth and entered the Understone Keep

Grabbed the pieces of dwemer scrap metal that is right by Cacelmo

Entered the ruins of Nchuand-Zel

Walked just past the cart with the stuff in it

Dropped the scrap metal and wabbajack pn the floor

Told Fandel I needed him to do something and got him to pick up the scrap metal and wabbajack

Told Fandel to follow me

Left Nchuand-Zel and the Understone Keep

Once outside, fast travelled to Riften and ran to the market

Then fast travelled back the the Understone Keep and re-entered Nchuand-Zel

Went to where I dropped the stuff

Picked up the wabbajack

Told Fandel to trade with me

Took the wabbajack from his inventory and WOO HOO I'm having too much fun lol

You should be able to use any follower