There have been some great artists, across music, acting, writing and so on, who are also great rebels. Does this apply to your characters? What form of rebellion are they using and how does it affect their creative side?
The UK has a massive industry based on its creative arts. I don't know how many millions are brought in thanks to Shakespeare and the tourists visiting Stratford-upon-Avon alone though I'm sure the annual sum must be considerable. So does your fictional world benefit from its own creative one? Does the benefit filter down to all sections of society or are only those of a certain background allowed to enjoy art?
How does the imaginative life work on your fictional world? Which of your characters sing, act, dance, write and so on? Are the arts appreciated or treated with contempt? (Even the Vikings appreciated story telling so there should be appreciation somewhere for arts in your fiction), Is creativity good? Yes. How does your fiction show that?