MMF is not the best for very humid climates. If you make figures, flowers or other decorations they will most likely droop/sag due to the humidity. I used to use MMF because I like it, but I learned the hard way. I have been using MFF (Michele Foster fondant) recipe. I am not sure if I really like it, but I am still working with it. Others on here rave about it. There are other good fondant recipes here on CC without marshmallows.
Hopefully that will help some. Also, like someone suggested about boxing up the cake and either bagging the box or tape it up and then letting it come to room temp is important. Controlling the temp and humidity in the cake area is important.
As for the food safety, kitchen inspections and other regulations each state is different. Where I live working under the cottage food law my state does not require any of those things as long as you register the business, get a tax id and a few other things. I wished I could get my kitchen inspected by the city or state. They won't do it since it is not required. I only mention this stuff since someone brought it up. Every state has their own rules.
As for the bubble, did you let your cake settle first before putting on the icing and fondant? I let mine settle overnight. Also, if your cake filling is to thick/to much/to runny and you did not use a dam then it can ooze out and cause a bubble.
As for the buttercream oozing out thru the tears, it could be that you have to much icing on the outside of the cake. I have put to much on the outside of the cake before and had issues with sagging and oozing out of tears. I have never used boiled icing so I can't help there. I use buttercream or ganache. If you use buttercream with butter and not something like Sweetex or other hi-ratio product the heat will affect it more. Butter has a lower melting point.
Due to 27 years of military life living in places like CA, South Texas, Key West and still in Florida I have learned a few things about humidity. The main thing is that it is a pain in the xxx and that I seriously do not like it.
Edited by ReneeFLL - 8/3/13 at 8:44pm