There is an Emails Clicked property in the Contact Properties (not the email properties) that will solve your fist problem.
I dont think there is a property for links clicked on pages but you can use the contact property Pages Viewed and apply an 'is greater than' rule.
Hope this helps.
Just wanted to second this question.
Given that a contact can only go through a rule once, I want to know if there is a way to configure the scoring such that each additional click gets you more points.
Yes, you can do this. Lead score rules always accumulate, so you could do something like this:
Hope that helps.