Like Bluebeard, I learned to play on an old zither banjo with the Pete Seeger book to get me started. The banjo had belonged to my Great Grandad Gilday who was of Irish descent but lived in Glasgow (Scotland) but he had passes away a long time before I found the banjo in an attic. In the banjo case was a plectrum, so I assume that is how he played it. I have no idea what sort of repertoire he played.
The 5-string banjo was certainly used in the UK during the Victorian and Edwardian eras for parlour music where different styles of Classical Banjo were played. Some were fingerstyle and others used a plectrum, but neither bore ANY relation to clawhammer or bluegrass. Try tracking down recordings of American classical banjoists Fred Van Epps or Vess L. Ossman. to get another slant on what music a banjo can produce.
I play Whistling Rufus with a plectrum. There are other occasions when joining in with Irish sessions, or as a slow tremolo effect behind a ballad, where instead of playing clawhammer, I will hold my index finger and thumb as though I had a plectrum, and play the strings with the nail of the finger as if it were the plectrum. It can be a very useful technique and, of course, it means that you are not actually holding anything, so can convert back to standard picking/frailing instantly.
Quack!
Geoff the Duck!