Just to emphasize for question 4, you do not have to create a GUI that graphically displays the shapes in your list. You also do NOT have to implement a sorting algorithm. All programming languages provide ways to sort instances of their collection classes. In Java, look up Array.sort() or java.util.Collections.sort(). In other languages, look for similar types of methods in the definitions of their collection classes.
The key thing I'm interested in for question 4 is are you demonstrating polymorphic behavior. Yes, you need to build a list of shapes and yes you need to sort them, but I'm more interested in whether you set up a type hierarchy and that you code targets the superclass and not the subclasses (i.e. code to an interface), etc.
Hope this helps!