Can I use Polymorphism in Page Lists?
Yes you can. Each Page List member is a Clipboard Page which can leverage this behavior the same as what was shown in the webinar.
Any behavior that needs to be performable for each member in the list needs to defined on the superclass, and can be overridden on the subclasses. Whilst iterating over a Page List at runtime, Rule Resolution will use the runtime class of the page list member of the current iteration.