We don't know what if any influence Dunn had on Wilson, or whether what was done at Princeton was simply a paper job by Dunn because we also know that professional James Swan made changes to what Dunn had drawn.
This was not Wilson's "primary qualification" for designing Merion, nor have I ever suggested that. It merely meant that Wilson was not a "complete novice with the knowledge of an average club member" as far as construction and agronomy as he humbly contended in his modest public statements, as he was on the Green Committee at Princeton as that course was being constructed. Neither was Rodman Griscom who had been head of the Merion Green Committee when the original course was designed and built...neither was Dr. Harry Toulmin who had been one of three men who designed Belmont according to Prosper Sennat's 1900 Philadelphia course guide.
As far as possible connections to Dunn, we also know that Wilson vacationed at Saranac in upstate NY, which was a Willie and Seymour Dunn production. It's likely that Wilson had some personal knowledge of Dunn, but not necessarily.
Of the Merion committee-men who designed Merion East, Rodman Griscom would likely have the best knowledge of Dunn, as he was the head of the Green Commmttee in 1896 when Dunn did work on the original Merion course, making some revisions to Willie Campbell's course, and perhaps adding a second nine (which is something unclear at this point).