Teasdale has 38 points (23 goals, 15 assists) in 57 games with Laval this season.
Now in his third AHL campaign, the 24-year-old has yet to make his NHL debut.
Allard, meanwhile, is pointless in five games with Laval after being acquired from the Los Angeles Kings at the trade deadline in early March.
Allard previously registered seven points (2 goals, 5 assists) in 35 games with the AHL's Ontario Reign earlier this year.
The 25-year-old has appeared in one game with the Canadiens, suiting up against the Vegas Golden Knights on March 5.
The Habs face the Islanders on Wednesday night at UBS Arena, before returning home for the season finale versus the Boston Bruins on Thursday night at the Bell Centre.