Hi,
Quebec is a nice place to live, don't worry too much about that! Just don't watch the news
For your elder son, he shouldn't have a problem, as IT is a big industry in Montreal, and it is mostly an english field. So he shouldn't have much trouble. I'd say Montreal is a safer bet for him than Ottawa. I would advise your children though to start picking up a few words, because telling employers all over Quebec and Ontario that you know "zero french" will be a turn-off, even if the job doesn't call for it, as they might have some coworkers who are french, or the boss might be a francophone.
As for business, it might be a bit harder to get a job in Montreal, but there are always jobs that have to liaison with the rest of Canada, so it is entirely possible. But that being said, having a solid knowledge of French will mutliply your job prospects. So it is impossible to say if you could get a job easily, as you will have less options, but options nonetheless.
Of course in Gatineau, living next to Ottawa could get you jobs in Ottawa quite easily, this is true. Although, it should be noted that even in Ottawa, bilingualism is often "an assett". That being said though, housing is cheaper in Gatineau than Ottawa, so many people do exactly what you do, live in Gatineau and work in Ottawa, so it has absolutely been done!
If I were you, I would check the job boards now. Check out monster, workopolis, indeed, craigslist, etc and see what kind of language requirements you see, or what kind of options are out there. Bear in mind that for Montreal, searching the west island will be more likely to give you english jobs.
Both cities are nice though, and not that far apart, so you could always try one, then move later! The quality of life is comparable, but in Montreal you will have a much older and varied immigrant community, in a bigger city. While in Ottawa, you can have more job security.
