Robert,
My favorite and friendly bank is Belize Bank but Atlantic Bank is the only Bank in the country that US Social Security will allow direct deposit of their checks to Americans living in Belize and the US Embassy endorsed them verbally in my resent visit. Scotia Bank may win the prize for the worst service and Heritage Bank is just too young and unorganized for my confidence. All the Banks are busy conforming to the new Foreign Account Tax Compliance Act (FATCA) .
expect to sign a pile of agreements and have documents as well as a utility bill (water or electricity) that shows an address here with your name on it.
Offshore Banking has been kicked in the head by US interference and lots of folks are getting out of them.
Exchanging US dollars for Belize or Belize for US at the Bank, IMHO, has always seemed difficult, unprofitable and unnecessary since the US currency spends at a rate of two BZ to one US everywhere but the banks.