No worries, anytime is fine.
1) I would say Mount Royal
2) There is St. Helene’s Island, which will be where the race will be held, so if they will be in town a few days prior or after would be quite the place to see. La Ronde is there. There are lots of trails, music outdoors on the weekend . The Expo 67 Biosphere is left, a lot to see. This can be connected from the metro/subway
3) Botanical Gardens is just magical to see
My favourite place is Old Montreal, so if they are staying downtown, they can easily walk, it’s cobbled streets. Very Europe-like, have a coffee and a baguette, and there is a lot to Explore
In the summer every week there is a festival, comedy, fireworks, jazz, etc. Hopefully we return to that.
Hope this helps. Can you tell I can’t wait for summer