Trottier, Danny Flynn and Tom Coolen will serve as assistants to Sabres coach Ted Nolan, while Irbe was named goaltending coach.
"I'm very happy with the group of talented hockey minds we were able to assemble for our coaching staff," Nolan said. "Each one of these coaches brings an extensive and different background from the hockey world and I'm confident they will help get our team to where it needs to go this season."
Trottier, a 1997 Hockey Hall of Fame inductee and seven-time Stanley Cup champion, served as an assistant coach with the Pittsburgh Penguins for four seasons (1993-94 to 1996-97) and then with the Colorado Avalanche (1998-99 to 2001-02), where he won the Stanley Cup in 2001. He also served as coach of the New York Rangers for part of the 2002-03 season and compiled a 21-26-7 record.
Trottier played in the NHL for 18 seasons and was an integral part of the dominant New York Islanders teams that won four consecutive Stanley Cup championships from 1980-83. After his time with the Islanders, Trottier played three seasons for the Pittsburgh Penguins, winning the Stanley Cup in 1991 and 1992. He had 1,425 points (524 goals, 901 assists) in 1,279 games.
Irbe played 568 games over 13 years as a goaltender for the San Jose Sharks, Dallas Stars, Vancouver Canucks and Carolina Hurricanes. Selected to two NHL All-Star Games (1994 and 1999), Irbe helped lead the Hurricanes to the 2002 Stanley Cup Final and represented Latvia at two Olympics (2002 and 2006). Following his playing career, the Riga, Latvia native served as the goaltending coach for his hometown Dinamo Riga during the 2008-09 season, before joining the Washington Capitals organization to serve in the same capacity from 2009-11. Most recently, Irbe worked alongside Nolan as an assistant coach for Latvia at the 2013 IIHF World Championship in Helsinki, Finland.
Flynn worked as an assistant coach for Nolan with the Islanders during the 2006-07 season. He was coach of the Moncton Wildcats (Quebec Major Junior Hockey League) from 2007-2013 and had a record of 222-141-47.
Coolen arrives from the Latvian national team, where he served as an assistant coach on Nolan's staff over the past two seasons, including at the 2014 Sochi Olympics.
The Sabres also announced Monday that Mark Jakubowski has been named assistant general manager, while Rob Murphy and Greg Royce have been added to the team's hockey department in the roles of director of scouting and director of amateur scouting, respectively.