Patrik Nemeth had the other Stars goal, who won for the second time in three nights. Texas has a 2-1 series lead in the best-of-seven Western Conference final. Cristopher Nilstorp made 20 saves in the win.
T.J. Brennan had both goals for the Marlies, who started the AHL playoffs with a perfect 8-0 record. Drew MacIntyre stopped 27 shots in the loss.
After Brennan tied it 2-2 at 10:15 of the third, Morin responded 59 seconds later, capitalizing off a Trevor Smith turnover in the neutral zone.
Biggs was in the Marlies lineup for the first time since Game 2 of the first round (April 26) replacing Jerred Smithson while Andrew MacWilliam (upper body) made his series debut replacing Dylan Yeo on the blue-line. Wednesday was MacWilliam's first game since a collision with Chicago Wolves forward Adam Cracknell in Game 3 of the second round.
Brennan nearly had his second of the game, and period, on a Marlies power play late in the opening frame as he wired a Spencer Abbott feed from the top of the face-off circle, but Nilstorp was there to make the save.
Nemeth tied it 1-1 at 3:16 of the second period beating a screened MacIntyre five hole for his first of the playoffs.
Henderson, who played for Steve Spott with the Ontario Hockey League's Kitchener Rangers, gave Texas its first lead of the game at 6:59 of the third tipping home the rebound off Brett Ritchie's shot for his first playoff goal.
Notes: Maple Leafs great Johnny Bower dropped the puck in a ceremonial faceoff. Game 4 of the series goes Thursday with Game 5 at Ricoh Coliseum Saturday afternoon.