If you attempt it, stick with the Ericas (heaths) as they tend to be more heat tolerant than the Callunas (heathers). Neither are very happy in high humidity, so fungal issues could indeed present a problem.

This online nursery has great info on which can survive heat and humidity on their site. They even have collections you can buy specifically for such conditions.

Here is a link that might be useful: Heaths and Heathers Nursery