I am from the maritime provinces and also had the experience of our family hosting an exchange student through EF when I was in high school. I have specific comments about the language, the city of Moncton, and the exchange student experience in Canada.
French language
Moncton is a bilingual city with a majority anglophone population. Pretty much every francophone will speak English, so even though the dialect is very strong, assuming your daughter speaks English, she would rarely be in a situation where she wouldn’t be able to communicate with someone. The schooling would be in standard French, but the local francophones speak " Chiac ", which is a very specially accented dialect that borrows heavily from English. This is a joke (they didn’t re-do the whole movie) but this fake trailer for the movie Toy Story in Acadien/Chiac is one of the funniest things on the internet.
Moncton
Moncton is the largest city in New Brunswick, but it is significantly smaller than Zurich and has fewer services. If your daughter does manage to snag a placement with a francophone family it is highly probably she will not be living downtown but rather in Dieppe or somewhere further east. Public transportation might not be an option, your daughter could depend on her host family to go anywhere after school or on the weekends, which could become very limiting. This would be generally true of almost anywhere she would go in Canada. Outside of city centres it’s very much a car culture. Also, Canada is very sparsely populated, so if your daughter’s idea of fun is travelling every weekend she will unfortunately not have many destinations within a few hundred kms. I am from Nova Scotia, and every time I go back I am staggered by how little people travel. Apart from going away on holiday people seem to spend the majority of their lives just driving their typical commute/shopping/social activity routes. Going away to a new place just for tourism as a day trip or weekend isn’t really a thing. Not that it’s a bad thing, just different. Compared to the bustle of Europe your daughter will find most places in Canada quiet and perhaps on the boring side. How does she normally spend her spare time?
The exchange student experience
When I was in my last year of high school in the late 90’s my mom decided we should get an exchange student. She’d already shipped two kids off to university and had two still at home, so was used to having lots of kids around and figured it would be easy to accommodate one more person in her household. We contacted EF and after we were vetted as a family we received a very large stack of applicants for us to sift through. A few of the applicants specified they’d prefer a specific location, but I think you and your daughter need to be aware of the fact that for all exchange programs there is a shortage of host families, and if you want to limit your search to one specific place you might not be successful in finding a placement. The girl we picked (who was from Aargau) had even specified she’d like to be near the rocky mountains if possible, but we decided to offer to host her as she seemed like the best fit for our family, even though we live thousands of kilometres east of the Rockies. She accepted as we were the only family that offered to host her. Two years later her brother applied for an exchange in Canada and also wanted to be near the big mountains, but he ended up with a family in rural Saskatchewan. Your idea of aiming for Moncton sounds nice, but being rigid about where she will go could greatly reduce the likelihood of her going abroad.
Honestly, I think you need to consider which is more important, the experience of living abroad or the language thing. If learning French really is the goal I’d recommend a true French immersion somewhere: Moncton is a very anglo place, since all the francophones speak English your daughter will certainly not get the same learning benefit as she would from going to France or Belgium (as you said Quebec isn’t an option). If she wants the experience of living abroad I’d recommend to lower your criteria to maximize the chances of her finding a place. She could of course express preference for a French speaking city, but mention that she is fluent in English and would also consider doing her exchange with an English-speaking family.
Another thing to consider is that based on my observations, host families tend to be larger families, which I guess makes sense. It takes a certain type of family to think it’s not a big deal to have one extra kid around the house. Would your daughter be okay with sharing a room? Does she need a lot of personal space and alone time? Would she be okay living in a rural area?
Regarding Canada, there are many great things about the country (the people really are super friendly) but for the most part it is very remote. The distances between cities is enormous and it is highly likely that your daughter would have relatively few opportunities to travel. Rural Canada is a particularly isolating place. My family is super sporty and also musical, so our exchange student was able to capitalize on this to meet people, and to also take up a new hobby to keep herself busy on the very long winter nights. She joined me in playing soccer with the school team, and she took up the piano as my brother was also taking lessons. She didn’t feel as though she was imposing on our family, as my parents were already were doing soccer and piano taxi service for their own kids.
In contrast, in the next village there was another exchange student hosted by a family with 4 rambunctious kids. The exchange student had a much more negative experience. She had to share a room in a cramped and noisy house, and was not able to escape easily. She ended up playing soccer with us just to have some time away from the host family and meet friends. But on the whole she found the year very challenging. The boy I mentioned who spent a year in Sackatchewan also found it tough. He was with a farming family with 4 kids in a very rural setting, there was very little to do and the siblings fought all the time. He stayed sane by getting super into running. (Of course these days there is the internet, so boredom is more likely to translate into spending way too much time online.)
Overall I think doing an exchange and of course learning languages are great things. However, more than language I think the consideration should be how your daughter will spend her spare time while abroad. You say she’s not sporty, but this could mean she prefers malls and makeup to skiing, it could mean she’s more into music and drama, or she could be someone who spends most of her time online.
My opinion: If living in a city will be important to her I’d recommend forgetting the French thing as Moncton is pretty much the only option, and even then I don’t think it’s a great one simply because English is the dominant language. There will be many more potential host families if the search criteria is opened to any city in Canada, and more again if rural is okay.
I have no connection to EF but will say that we had a very good experience, and our exchange student did as well. She spent her first two weeks in Canada in Toronto meeting something like 100 other incoming exchange students and they did lots of sightseeing but also having seminars about the exchange student experience and how to manage expectations. Our regional coordinators were excellent, and served as mentors to all the students in their region, often having them over for dinner, and offering them a place to sleep if they wanted to have a short break from their host families. We are still in contact with them to this day.
Anyways, this is getting a bit rambly so I’ll stop here. I’d be more than happy to chat about Canada and doing an exchange there if your daughter would be interested. I wish her good luck!