Which story option?

The Color Kingdom AU (which really needs to be given a name) won the poll to have a story written about it first. However, I have come to realize that I actually am completely unsure of what to write about

In the AU's unfinished state, I don't believe that writing about the main plot would be a good decision, so this will have to be a side story that ties into the main story somehow. The question is, which part of the AU will get a side story?

If you vote for any of the first three options, please comment as this will greatly help me get an idea on what others would like to see most