I am planning on making my son's first birthday cake with the theme being Mickey Mouse. I am all over the map with designs but know I want something along the line of what I have attached (taking what I like from the three of them). I want to make the fondant but use a marshmallow fondant so it doesn't taste gross. I want to try to make the fondant tomorrow night but the more I read the more im confused about whether to do gum paste or fondant.

I know im going to make the top hat part out of rice krispie treats molded in a bowl but do I use fondant or gum paste to cover the mold? Also what about the ears and the letters / stars on the last image I have attached - what will hold up best. 

I think the rest of the cake I can do fondant? Thoughts?

Can someone please help me. Also how far in advance can I make and decorate the cake. I have little ones of my own and then will have company and family all over the day before the party. 

Sorry I rambled - please help!!!

The ears can be thin rkt dics (same as the hat) then before you cover them w/fondant sand it a bit smooth   These elements can be made now:)   Those stars w/letters also can be made now from fondant that has a Some cornstarch added .  Make them thick enough to stick a skewer in & let them dry away  from any light especially sunlight   As for how far in advance to make the cake probably not more than 2-3 days so it’s still fresh 

.