Barzal was selected with the 16th overall selection in the first round of the 2015 NHL Entry Draft by the New York Islanders on Friday.
Successive moves Monday and Tuesday saw the team add defenseman Brandon Schuldhaus and import center Gustav Olhaver.
In 31 games at the AAA Bantam level last season, Brown contributed 41 points for his Lions team including 18 goals.
Young players for the four Western Hockey League teams in Washington will be exempted from certain labor laws that would have restricted their practice, conditioning, playing time and made them subject to the minimum wage.
With the exchange of overage players, Seattle remains set at the limit of three. In addition to Watson, the Thunderbirds are expected to return 20-year-old defensemen Jared Hauf and Jerret Smith.
The Thunderbirds selected Elijah Brown, a forward from Edmonton, Alberta, with their first round pick in the 2015 WHL Bantam Draft Thursday. Brown scored 18 goals and delivered 23 assists in 31 games in Bantam this season.
The 20-year-old Kozun had the best season of his junior hockey career by posting a .915 save percentage and 2.41 goals against average in 60 games.
The offseason is of vital importance to Seattle, a team that played 11 rookies over the course of the 2014-15 season. All are expected back for the 2015-16 campaign including goaltender Logan Flodell who will be counted on, at least in part, to replace WHL Top Goaltender finalist Taran Kozun.
Tyszka was Seattle’s first-round pick (16 overall) in the 2014 Bantam Draft. He joins a defense unit which returns Ethan Bear, Jared Hauf, Jerret Smith, Turner Ottenbreit and Sahvan Khaira for next season.
The Winterhawks handed Seattle a 5-4 defeat in Game 6 of their first-round series. The loss meant the end of a handful of Thunderbirds’ careers, including that of defenseman Shea Theodore.