Since we just did this, I'll step in.
As for the bank accounts, be sure to bring letters of reference from your stateside bank. If it is to be a joint account, make sure the reference is for both of you. Establish any wire transfer needs before you get down here. We finally gave up on Bank of America...that's another story.
We established a Belize corporation which owns the business. We do not take salaries, but I "manage" the business on a day to day basis. Our plan was to employ Belizeans when we got the business up and going. If you plan to purchase a business, you are probably going to be in a different situation.
I used a company in Belize City to help us through all the paperwork.
Best of luck to you. It is a wonderful place to live and as close to sane as you are going to get in this crazy world...