Hi,
Thanks for your post. Given the information you've shared (and provided you score a minimum of 700 on the GMAT), I think you can certainly be competitive for admission at the schools on your list. Your international work experience in Japan as well as your extracurricular activities will certainly help you stand out in the pool. As I am sure you know, you are indeed part of a very large group of bschool applicants. Successful bschool candidates not only have the academics and work experience, but are also able to demonstrate a uniqueness thus allowing them to stand out in the pool. I encourage you to think about your extracurricular activities and find ways to incorporate them into your essays - in particular to address your leadership skills since it sounds like your flat organization has not allowed for leadership opportunities.
Regards,
Stacey