Just a guess but I'd try the acoustic-sim with the cab module off, and maybe add a pitch-shifter preset. And, of course, use banjo picks. The best way to switch between rigs is to set up a Performance.
try the "Kemper Banjo" profile von B.Ruppert.
it´s a modeled Banjo sound from Rolands VG-99 profiled with the Kemper, weird but works
Just remove all the musical sounds from a guitar
Banjos are cool. Get one to make a sad sound.
It ain’t in there.
Just a guess but I'd try the acoustic-sim with the cab module off, and maybe add a pitch-shifter preset. And, of course, use banjo picks. The best way to switch between rigs is to set up a Performance.
I'll give that acoustic-sim a shot, and yea, its a performance wtih verse is rig1, pre-chorus is rig2, etc.. Thanks !! 
There was one floating the Rig Exchange from Ruppert years back that was pretty good , probably still there
when i had my Helix + Variax, i've made a preset with an intro/verse with a banjo (and solo with a Gibson sim on a Marshall)
For this part of song, i had only a "studio" amp (+ some fxs) + variax banjo simulation.
I assume that Variax is just an IRs store (or close to).
I haven't tried it (yet 
), but today, i would built an equivalent with acoustic sim and a banjo IR put in the cab block 
