Both contracts carry an annual value of $750,000 in the NHL. Heatherington carries a $250,000 value in the AHL while Sherwood carries a $150,000 value.
Heatherington spent last season in the KHL with Astana Barays where he had two goals and seven points in 41 games.
A second round selection by Columbus in 2013, the 26-year-old has played 313 AHL games and was a Calder Cup champion in 2016 with the Lake Erie Monsters.
"Dillon is a defensive depth player for us," Dorion said. "He will bring leadership to our young group in Belleville. He plays a big, physical, defensive game and he brings a lot of character."
Sherwood played six games with the Columbus Blue Jackets in 2020-21, notching one assist. He also played nine times in the AHL with Cleveland where he had three goals and four points and has lined up 110 times in his AHL career scoring 29 goals.
"We're happy to have Kole join us," Senators general manager Pierre Dorion said. "He's a good-skating up-and-down winger with lots of drive and energy and we like those attributes and have liked this player for a while."
Both Heatherington and Sherwood have played 11 career NHL games while the former has also appeared in one playoff game.
