In order to submit does Derpy have to be the Main-main star. Or can she be a co-star?

4059150 That's a good question. I'd like to know, too.

4059150
Hello there,
I apologise for the "somewhat" late response, but I do feel it would to be clear any confusion over this topic.

While our great and benevolent consumer of muffins does need to be the start of the show, or story for relevance sake, she must be a consistent part of it, a continuously recurring side character, if you will.
For example,
"Doctor Whooves & The pending title" - Copyrighted by nobody.
Doctor Whooves takes the title and lets assume 90% of the story focuses on him and his struggle to entitle his great detailing his many great adventures, much like Daring Do.
However, should Miss Hooves make a point of being vital to the story, appearing in several parts of it, being mentioned, talking, doing things, etc. Then yes, the story may be added as while she is the main character, she is a somewhat consistently important role, within the story.