You're going to have a tough time at HBS, Stanford and Wharton to be honest even with a higher GMAT score -- you'll be a stretch, but as a plain vanilla investment banker without any unique or stand out achievements (athletic, artistic, social/nonprofit, political, etc.) in college or after banking, you will have a tough time separating yourself from the pack. The other schools you should be competitive for - no real safeties in there (and Columbia you're applying in Regular Decision, which will only make it tougher for you than had you applied ED).
As for addressing your leaving after 2 years - that's what you did. You said it yourself. They didn't invite you back, but you weren't planning on staying anyways. You wanted to do something else, which is why you left - simple as that. You're not the only one to have left after 2 years. What will be harder to address is why you decided to teach English in Japan (which adcoms will see as a vacation more than a real job - because these "teach English in Asia" experiences tend to get a bad rap for having no standards when it comes to hiring - so long as you speak English fluently).
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