The photo found of PN w/3 guys.. looks like it's his racing buddies. The guy on our right, I believe is race legend Mario Andretti.
http://www.nydailynews.com/entertainment/tv-movies/man-stumbles-paul-newman-suit-connecticut-basement-article-1.1179101
The people on that picture are : Carl Haas (co-owner of his racing team), Michael Andretti, PN and Mario Andretti).
I doubt the suit Peter Gamlen found came from "The Color of Money" wardrobe. I don't remember PN wearing it in that film. Besides that guy found other clothes, among them a sports jacket (with the photograph inside), and PN doesn't wear that kind of clothes in that film.
I don't remember when, but I know that, one day, PN gave away most of his wardrobe. The clothes found in New Haven must be a part of it.
As for the blue suit, I saw pictures of PN wearing a suit that looks the same at the following event :
"The Hole in the Wall Gang Camp Art Auction" on May 4th 1987 (Getty Images)
And at another event :
"New York Friars Club roasts Chevy Chase" on October 17 1990 :
http://www.tvguide.com/celebrities/chevy-chase/photos/144376/82855