Suzuki is a guy you trade for Pettersson, not Horvat lol.
Gallagher would be a great piece to add to play with Horvat, not for him.
If the Canucks had the surplus assets, I'd love a trade around Tanner Pearson ++ for Gallagher. Get Toffoli his buddy again and get the Canucks another win now piece. But Pearson as a center piece isn't nearly enough (but maybe it is if you add Podkolzin as one of the +'s), so while it isn't happening from the Habs perspective, that would be a nice forward group.
Miller - Pettersson - Boeser
Hoglander - Horvat - Gallagher
Garland - Dickinson - MacEwan
Motte - Sutter - Highmore