In the case of English 101, for example, the major assignments are three major essays and one group project. Each student must complete the required work for these four assignments in order to pass English 101. The remaining assignments are averaged for a significant portion of your grade. Of course, the best approach is to do all your work. When students begin work on a subject, they may transform it, even change it entirely, up to a point, but then they must stay with it.
Students reach the point of no return for subject selection at the proposal stage.
After that, new subjects require a new proposal. Now is also the time to make clear what I will do when a project is posted which does not meet the minimum length requirement. So are ten sources. However, I have sound reasons for making a minimums clear. Finally, a shortfall may result in my not accepting the project at all for credit.