If luggage does not come out quick at YYZ that will be tight. OTOH 1.5 hours at YUL is OK.

But do you really have only 1.5 hour at YUL? It appears the DTW-YYZ flight arrives at 15:56, so the YUL flight leaving at 17:30 arrives at YUL more than two hours ahead of the BRU flight.

So, if you miss the flight to YUL, the next one still meets the 40 minutes MCT at YUL and you should be fine on that one.

They can also rebook you through FRA or LHR in Toronto if your first flight gets more delayed.

So I would not worry too much, lots of options.