While I can't provide recommendations of any specific schools, you might find this forum post useful for the rest of your questions, as I answered some quite similar questions recently here: www.expatarrivals.com/answers/what-kind-of-school-is-best-in-montreal-for-our-three-young-australian-children
The short answer is that you will probably not be eligible for English-language public schools in Montreal. In French public schools, there may be some support for English speakers but it's difficult to estimate the extent of that support. For some more info on the schooling system, have a look at the Expat Arrivals Education and Schools in Montreal page.
You may want to consider looking into subsidised private schools as an alternative to international schools.
Have you secured employment there already? If you're relocating for work, you may be able to negotiate an education allowance as part of your relocation package.