Welcome to the forum!
I hope what I mentioned below is taken in the spirit of constructive feedback - I just felt that given how much you wrote, I owe it to you to be as candid as I can - but noting that this is simply my opinion and perspective (which you can completely disagree with).
First, I think you're projecting how much you value the "brand" onto others -- assuming that others actually care about it as much as you do. Trust me, I know where you're coming from with this whole brand thing, but I'm telling you it's not as big a deal as you think as the MBA becomes more and more a distant memory.
Maybe your fellow peers may fawn over brand names of schools, but not folks who are more experienced than you. Just because a lot of people have MBAs from certain schools doesn't mean that they necessarily value such a degree. The folks who hold some of the most cynical and jaded views about the value of the MBA come from those who went to H/S/W.
Unlike other forms of education, an MBA isn't really an investment, but a consumption good. It's more like a car than a house -- it's a depreciable asset.
Anyhow, you can believe what you wish to believe, but be careful about assuming that others will value it as much as you do, especially the longer you're out of school.
In short, I think you're a middle-of-the-road candidate for schools like H/S/W. I hate to bring in the race card, but you really have to be able to show that you're not the stereotypical Asian-American/Canadian guy. Can you show through your experience that you are better with people than you are with numbers? As you probably know, the stereotypical Asian-American/Canadian applicant is someone who is studious, reliable, analytical, and straight as an arrow - in other words, characteristics that make for a great worker bee. It may be an unfair stereotype, but remember that this process is subjective, and individual adcom's own preconceptions will come into play (and when they see so many Asians with similar characteristics regardless of their pre-MBA occupation, it's hard not to form strong preconceptions even if it's wrong to judge individuals based on those preconceptions).
From what you wrote, it's hard to say how you are much different from the other Asian finance guys applying. You can't rely on "numbers" or "brand" or "credentials". You need to show that you have the ability to be a great boss to work for someday. Someone who has gone against convention (a hurdle exacerbated by culture/upbringing that stresses conformity over originality). Someone who knows how to color outside the lines. Someone who isn't your typical studious, obedient, by-the-books Asian.
You have to be able to show that you're not just an "exceptional associate" but a "high potential partner". Lots of finance types can show that they have the work ethic, analytical skills, execution, blah blah blah to be great associates (pre or post-MBA), but relatively few can convince an adcom that they have the hustle, leadership, and people skills to be great partners/executives. It's all about interpersonal, team and leadership skills. Your ability to influence and persuade people. It's not about "executing processes" but about building relationships, having the ability to connect with people, etc. Stuff you don't learn in school, but stuff you will more likely learn in extracurriculars such as team sports, arts/music (playing in bands), community service, politics/activism, and any sort of group-oriented activity.
They are looking for queen bees, not worker bees. Also because there are more queen bee types applying to these top schools.
And no, there isn't some quota for Canadians - it's neither an advantage nor disadvantage, and they will be benchmarking you more or less based on your occupation, not your nationality. You're an Asian-American/Canadian finance guy. That's fundamentally what they'll see you as.
As such, there are plenty like yourself who will be applying to these schools who went to Ivies, went to *ahem* McGill or Queen's (which have a long history of alums at these three b-schools), worked at Goldman, Morgan, McKinsey, Bain, etc. and worked at top tier private equity shops. The profile of many Canadians who apply and get in aren't much different than the Americans - lots of blue chip bankers and consultants. In terms of pedigree, you will have less than they do.
So it comes down to the "man behind the resume". It's not about your firm being founded by HBS guys (that's practically irrelevant). It's not about your age (you're fine), your analytical credentials (CFA, strategy execution, blah blah blah). It's whether you can show yourself to be someone who isn't conventional. Having few extracurriculars doesn't really help, but you are who you are. All you can do is focus on the essays and interview, and hope for the best. Without a lot of luck, I honestly think your chances are slim - not because you don't have a *strong* or *solid* profile, but you don't come across in your post as someone who is substantively different from the hordes of other Asian finance dudes applying (and with less pedigree). That may be hard to hear, but maybe it can open possibilities in your life/career perhaps that you may not have thought of before. Dare to be completely unconventional and crazy that may horrify your family, even if it doesn't mean going to b-school, or collecting brand names, prestige, status, etc.
And you should apply to other schools as well. Like Columbia, Chicago, Kellogg, Sloan, Tuck, NYU, etc. I know you said you're not elitist, but you're not above these schools that are not H/S/W.