Scott revealed former Eagle Ben McKinley will also make his first appearance in Kangaroos colours.
Scott said the rookie-listed Pedersen will be elevated to North's senior list this afternoon, after Ayden Kennedy was recently placed on the long-term injury list.
Atley, 18, is an explosive midfielder who was the club's first pick, at No. 17 overall, in last year's NAB AFL Draft. Medium forward McKinley, 24, was acquired in last year's trade period from the Eagles, while running defender Richardson, 23, and utility Pederson, 24, were both plucked from the VFL, where they were standouts with North Ballarat and the Box Hill Hawks respectively.
Scott said none of the four new boys had been selected with an eye to the future, all having established themselves in the Kangaroos' best side over the pre-season.
"They've been picked on form," Scott said at Aegis Park.
"They've forced their way into our best side and we'll take over the side (to Perth) we think can get the job done."
Scott believed Pedersen would give the Kangaroos flexibility with his ability to play as a key forward or back and in the ruck, and it was unlikely he would be named as a substitute.
He said North had planned extensively for the new rule - in which the interchange bench will reduced from four players to three players and a substitute - but, like most, would have to wait to see how it operated in practice.
He said North Melbourne's win over the Eagles last year at Paterson's Stadium would be irrelevant on Sunday with both young sides evenly matched.
"You look at the West Coast line-up, they've got a lot of talented young players who I think will be very good players in the future," he said.
"And people have said that about us, too. So in terms of age and experience we're around about the (same) mark."
Scott repeated his comments earlier this week that forecast hot weather conditions in Perth on Sunday would not adversely affect his side, citing North's NAB Cup Challenge game against the Western Bulldogs in 31-degree heat at North Ballarat a fortnight ago as "perfect preparation".
Sunday's game will mark the 150th AFL appearances of North players Daniel Wells and Michael Firrito, and Scott was full of praise for both.
"Wellsy's a player who oozes class and grace… his grace on field can sometimes be misunderstood for a lack of urgency and that's a fallacy," he said.
"I've got no doubt Daniel Wells' best football is ahead of him."
"(Firrito) is hard, he's aggressive, you know exactly what you're going to get from him. He's extremely coachable, follows instructions to the letter… (and) there's not too many players who are more versatile than 'Spud'."
