Camper, 27, scored nine goals and 25 assists for 34 points in 64 games with Hershey (AHL) in 2015-16, and finished second in the AHL with 17 points (nine goals, eight assists) in 21 postseason games as the Bears reached the Calder Cup Finals.
An AHL All-Star in 2012, Camper has played 328 career AHL games with Hershey, Binghamton, Springfield and Providence, totaling 65 goals and 169 assists for 234 points. He has 15 goals and 20 assists for 35 points in 38 career Calder Cup Playoff matches.
Undrafted out of Miami University, Camper has one goal in three career NHL games, all coming with Boston in 2011-12.
MacWilliam, 26, spent last season with Manitoba (AHL), scoring one goal and 14 assists for 15 points in 72 games played. A 2008 draft choice by the Toronto Maple Leafs, MacWilliam spent his first two pro seasons in the Leafs system after playing four years at the University of North Dakota.
MacWilliam has played 189 AHL games with Manitoba and Toronto, registering four goals and 27 assists for 31 points. He has two assists in 12 career NHL games.
Stollery, 28, spent last season with San Jose (AHL) scoring six goals and 18 assists for 24 points and 65 penalty minutes in 67 games played.
The native of Camrose, Alta., has appeared in 276 AHL games with San Jose, Worcester and Lake Erie, totaling 27 goals and 88 assists for 115 points.
Stollery has also played 12 career NHL games with Colorado and San Jose.