Hi there,
Congrats on the solid GMAT! Hmm, certainly I would have to say that schools generally encourage international applicants to apply early in the season for many reasons... and also that admission across the board can be tough in the final rounds simply because they've already given out so many seats by then. Of course if you do manage to stand out and grab their attention and they feel you'd be a great addition to the class, it can still happen.
There are a lot of things we don't know here, which could come into play... your academics; more info about being an entrepreneur (since you also mention other work? Not sure if the entrepreneurial experience is recent, or extensive, or what you've accomplished etc); your outside-of-work activities; overall accomplishments and leadership; goals/rationale....
Regarding the visa questions, you could reach out to the schools and ask about your concerns and the details at any point.
To discuss your situation further with one of our consultants, feel free to sign up for a free 30 minute consultation at any point if you are interested, at
www.mbamission.com/consult.
Good luck!