Fondant/Buttercream Problems. Desperately seeking help.

I live in Bombay, India - HOT and HUMID (very humid). The buttercream i make is the Magnolia Bakery recipe. I ice the cake and have to keep popping it into the fridge every few minutes else it gets all runny/gooey. I have tried making it stiff with more icing sugar-  but that just makes it difficult to spread on the cake. So - i end up serving only cold cakes. Which is OK for the home - but i have (accidentally) started a small out-of-my-kitchen made to order cake biz and It gets difficult when i have to make for others. Wilton recommends a buttercream recipe for high humidity places - but that used veg. shortening/crisco - which is not available in India. the veg shortening that you do get does not mention anything about trans fats - so i'm sure it has them. I don't want to use stuff loaded with trans fats.

My bigger problem is with fondant. For this I use the Michele Foster recipe. I always have to use more than twice the amount of icing sugar she recommends to make it usable. else it's waay too sticky and un-rollable. I first refrigerate the cake to make it easier to cut. then i crumb-coat it and ice it with buttercream. Refrigerate it again. After this i roll out the fondant and cover the cake. The fondant immediately becomes all gooey, shiny, sweaty and tacky :(. I cannot make anything which is 3D as it wont stand up. It's only flat/cut-out stuff that i can lay on the cake. If i leave the cake out - the fondant begins to sag and get super tacky/sticky. If i refrigerate it - the moment it comes out - it starts to sweat and gets the same way. What can i do about this problem? Any and every bit of help would be appreciated. Any alternate recipe which works for those of you who live in hot and humid climes?

Thanks for your patience to read this. Since i'm entirely self taught - i have all sorts of problems :D

PS: I cannot use SMBC or IMBC - cos most people do not want eggs in anything. So i specialise in eggless cakes and frostings.