Q:

Know if a MovieClip will trigger a function

Ok, so I have this movie clip X and I need to check if it has a listener to a function... I know about the hasListener thing, but I can only send an event type to it right?  Like MouseEvent. CLICK, or anything like that.  
What I need to know is if I can get an exact function that will trigger when the event is dispatched.  willTrigger() can help me with something?  

A:

NO, you can't get the function object which will be called for a particular event.  willTrigger won't help either.  If you need the listener function later then you need to remember that yourself.  
The best way to remember listener functions will depend on your particular need.  One possible way is to extend the MovieClip and override addEventListener to save the listeners in an object.  You can use the event type as the key and an array of listeners(every event type can have more than one listeners) as value.