This is a tourist oriented website, and while starting a business is a common dream for many who visit this forum, there are very few people here who can answer your question in anything other than a second hand account.
That being said, there are a few of us here who have started businesses in Negril and Jamaica and have been successful. And come to think of it, there are really only a few non-Jamaicans that I know who have started up long term thriving businesses in Negril.
There are things that need to be done in order to acquire all the necessary paperwork and legal status for both you and the company you want to set up. I would not call them obstacles, just the usual steps that need to be taken when setting up a new business. Being a foreigner will add a few steps, but nothing daunting.
The best initial advice I could give you is on your trip in September, search out some of us who have been successful here and listen to the advice that you get from these people. I took about 3 years of research here before starting my business, Negril.com, back in 1995. The research I did made the whole thing much easier.
As a footnote, I lost count years ago of the number of people I have seen move to Jamaica, invest much more money than they anticipated, and went home empty handed. Most feel that Jamaica was to blame, but in reality it was their inexperience and lack of research that got them into trouble in the first place.