Hello Rhys, you have a clear idea of the story you want to tell so now it's a question of using sound to create the appropriate environment. Think about where you might be able to record some ambient noise that sounds like a circus tent - what would it sound like? There would undoubtedly be some music, but be very careful that the use of music doesn't obscure the narrative of your animatic - your idea of using percussion grooves is good, and if these are added over the 'bed' of background noise it will help create the sense of a party or carnival atmosphere. You need to try and tell a story with your sound, and the viewer needs to believe in the world you are trying to create. Think carefully about whether they can follow your chosen narrative just by listening to the sound - close your eyes and listen to your soundtrack and see how easy it is to describe what is happening.