There is an actual Peter de Vries? Is that a coincidence? Or something Frank Herbert deliberately put in?
The reference: https://dune.fandom.com/wiki/Piter_de_Vries
de Vries is one of the most surnames in Holland. It literally means "from Frisia (the modern day dutch province of Friesland)".
So Peter de Vries is effectively the dutch equivalent of John Smith.
Peter R De Vries was a prolific crime reporter / journalist who did exceptional work in the Netherlands for many years until he was murdered in cold blood.