The Effects of Heat and Humidity

I just made almost 2 dozen colored chocolate butterflies for my step-brother's marriage cake (in 2 weeks' time) following your instructions from the Whimsical Bakehouse book closely.
I made them fairly thick for fear of breakage. The problem is, here in Singapore the weather is about 88-90 deg during the day. I had to place the transfers in the freezer overnight to harden, and this morning after flipping them over and putting the fan on them to remove condensation; they have softened to the point where they are difficult to handle. The polka dots are worse - being smaller. It looks as though the transfers will have to stay refrigerated or frozen until the cake is ready to be decorated.
I am really worried they will be too soft to stay in shape on the cake, and am also wondering whether their weight will cause them to slide off the cake.
Any advice for a newbie? I don't know if the chocolate transfer method will work well in our climate!

The summers in New York can be quite hot and humid but the temperature fluctuates and is not consistently in the high 80's or 90's and most places have air conditioning. The air conditioning in our decorating room in the basement of our bakery is not strong so we also run into some difficulty with the chocolate. Mainly the chocolate gets lumpy from being exposed to the humidity. Ideally chocolate should be stored in a cool and dry area.
I store my finished chocolate decorations at room temperature but before applying them to the cake I flash freeze them for about 2 minutes to harden them so they can be handled without breaking or melting in my fingers. If you can store your chocolate decorations the same way without them spreading or losing their shape/detail, do so, then flash freeze. That way you don't have to worry about condensation.
Store your finished cake in refrigeration, and if the serving area is not air conditioned make sure the cake is in shade. Direct sunlight will melt not only the chocolate but the buttercream and fillings too. Normally we recommend serving the cakes at room temperature, but for you I'd say refrigerate it until just before presentation or serving. If you need to transport the cake, again, make sure the vehicle is air conditioned, and try to keep it in the shade.
I made my own wedding cake (it was an unseasonably hot May day) and the cake was left in the sun. Some of the chocolate decorations slid down the side of the cake. This leads me to my next bit of advice for such extreme weather - keep the applied designs on the top of the cake or around the bottom border, not on the sides.