First off, BRING WARM CLOTHING. IT'S COLD AS FUCK THERE. Secondly, I love somewhere east of Toronto, where there are a lot of white people. Not so many Asians here.
But about your concerns:
1. I'm not sure if it's that big of a deal. But please, please please please do not demean your culture just to fit in with a certain clique of people. There are many decent folk in Ottawa (and anywhere in populated cities like Toronto), and from what I've heard, it's pretty diverse there. University of Ottawa is pretty well known in Ontario, so there are quite a few international students there.
If your height still bothers you, remember that you've had military training. Not very many people have had that in Canada. Working out is always a good thing. Also, try to watch a few western comedies. Nothing breaks ice faster than a good joke.
If there's one thing that I've learned from growing up in Canada as an immigrant, it's that you have to know how to be selfish. I'll elaborate on this if you want.
2. I've visited Ottawa twice. Nice people, very welcoming. Though, this was downtown Ottawa near the Parliament building, so this was a touristy area. It's a beautiful place. I've heard you can skate down the canal to the University of Ottawa.
3. I can't answer that, I don't have that experience.
4. I can't answer that, I don't have that experience.
Well, I think you've experienced the extremes of the bunch. Those who go to Korea or Japan, and are disappointed of their expectations, might have based their entire perspective of Asians on what they watched. Mind you, in the west, Asian females are portrayed more often than Asian males. Asian males have been left to "play outside" while the females are free to come and go. This means that you may experience slight misconceptions, and even casual racism. Canada is a pretty diverse place, mainly its major cities like either in Ontario or British Columbia. The people who are in the University of Ottawa most likely know how to interact with other people of different cultures.
I can't help you on that, I don't live there.
Canada has something called the "Multiculturalism Act." It's not perfect, but it works. This was enacted sometime in 1973, so there has been some time for it to grow. If anything, this shows that Canada is willing to accept other ethnic groups, on a political level. This act also effects businesses, having a quota to fill to be more diverse. Seems kind of racist, but whatever I guess.
A lot of Canada's culture derives from American culture. I think we're the much toned down version of the US, but we take pride in our differences from it.
In short, you might experience racism, but not as bad as South America. South America seems like an extreme case of ignorance. We're much more chilled up here. Enjoy being yourself, Canadian universities are fairly diverse (so long as it's in a major city). I'm sure you'll find other Koreans there as well.
I hope this helps.