Too bad this competition wouldn't accept choir, would sounds SUPER EPIC with choir in it.

Amazing!!! Just my personal preference, if you wanna incorporate dissonant harmony and consonant harmony together, the biggest problem is that the audience will always perceive the dissonant harmony as a "wrong chord" or "wrong note". It suit the playful style really well, but what you can also do is make those dissonant harmony longer and repeat more often. By doing so, you reinforce the idea that "No, this is not wrong note, I want this."

For first time orchestral composition this is actually pretty good!! (My first time probably is worse than yours lol).

I feel that certain spots have dissonant that didn't resolve properly, I'd recommend study a little in non-chord tone (or embellishing tones): http://openmusictheory.com/embellishingTones.html