You are asking a couple of really good, but really tough questions.
First, the question of entrepreneurship. It's not going to matter what concentration you seek from an MBA program - it's going to matter what you put down for your career goals. The rule of thumb is that unless you are a SERIOUSLY passionate entrepreneur who has displayed those chops with several attempts (past or ongoing), b-schools tend to not buy "I want to get an MBA, graduate, and start a business." There's simply no evidence that this is the way you work and operate, so what you become is a wild card. Instead, it is best to define some short-term goals that A) the MBA program is confident it can help you obtain, and B) will help you more toward those start-up dreams. There's almost no reason to state starting a business as your immediate goal - there's too much that can be learned by going into a broad post-MBA job (consulting, rotational programs, operations, etc.).
Second, your GMAT score is going to hurt you. The good news is that you are not in one of the super crowded demos (white male, Indian male), so you will get a bit more wiggle room, but not much. Below 670 is really hard at top 15 schools because they have to dip so far down below their average. The danger is that even if you have a great story (sounds like you could have the makings of one), they might not even read it because they have thousands of files to read and they sometimes screen out lower GMAT scores. Did you engage in hard core prep for the GMAT? If not, it might be worth hiring someone to help you max out your score. Even 20 more points would help a lot.
As for your school choices, it's a nice broad mix and that is good. You want a wide range of programs and you want a lot of them when you have an outlier stat, like your low GMAT.
I hope this helps.
Paul Lanzillotti | Founder| About | email@example.com | 877.866.9251
Schedule a Consultation | Twitter | Blog
Download "How To Apply" Guides | INSEAD | Columbia | Harvard | Wharton