It's gonna be first contest ever... the rules are very open, it has to be a Bday cake and choose flavors and fillings and we have to make 2. 1 for the lights and other for tasting.
I'm not sure if I should go for adult or kids themes!! But I'm more towards to kids, 'cause it's very fun.
I can't decide the flavors, should I go for the classics (like buttercreams: strawberry, chocolate, raspberry, apple, jams, curds, etc) or should I try something different (but delicious of course) like mango or passion fruit or pineapple fillings, mousses etc) I'll be judge by popular vote so I don't want to make something really weird like pistachio cake with mojito filling lol (just an example lol). I don't want to scare people's palate, but the country I'm from, people are used to more tropical fillings and very sweet fillings, or curds (buttercream is almost never used), I don't know if different fillings would be well accepted, even though I'm sure they are delicious.
They said I can use more than 1 cake flavor or fillings.
Also, I don't know if I should make 2 identical cakes, or different ones. I don't really know which one is gonna be judged for the look. They said they expect people to duplicate the cakes. Weird.. lol
I've checked the galleries and google for ideas of bday cakes and I want to make them all!!!!!!!!!!! lolol
Please, some light at the end of the tunnel?

I'd go w/something slightly different both for cake and filling.
As you said you don't wamt to be too 'far out' but different.
Yeah, kid's cakes can be fore fun to design. However a humorous cake for a man also could have lots of merit and show skill.

is it passion fruit to different?

One of the best-tasting and best-loved cake combos I've done is a white ginger cake w/ (cooked) mango filling and guava-passion fruit IMBC.

Should I go for buttercream or fondant? I'm better working with fondant (and I love much more to work with it), but I know most of people love buttercream even though my fondant tastes like marshmallows

Do what you do best.

I forgot to say that your combo sounds AMAZING!!
thanks for the tips from both ... I'm so "undecided" lol

just wanted to add that I've seen a lorann flavoring that is "cotton candy" how wonderful would that be for a kid's flavor?