What Are "foil", "Complication", and "Dramatic Reverse" used as drama terms?

Answer 1

Here is what I found. Hope it helps!

Foil
A character in a play who sets off the main character or other characters by comparison. In Shakespeare's "Hamlet" Hamlet and Laertes are young men who behave very differently. While Hamlet delays in carrying out his mission to avenge the death of his father, Laertes is quick and bold in his challenge of the king over the death of his father. Much can be learned about each by comparing and contrasting the actions of the two.
http://www.tnellen.com/cybereng/lit_terms/terms/2terms.html#Foil

Complication- A series of difficulties forming the central action in a narrative.
http://library.thinkquest.org/23846/library/terms/index.html

I think this is Dramatic Reverse. I'm not 100% sure.

Theories of tragedy
The philosopher Aristotle theorized in his work The Poetics that tragedy results in a catharsis (emotional cleansing) of healing for the audience through their experience of these emotions in response to the suffering of the characters in the drama. He considers it superior when a character passes from good fortune to bad rather than the reverse; at the time, the term "tragedy" was not yet fixed solely on stories with unhappy endings.
http://en.wikipedia.org/wiki/Tragedy

Good luck! Let me know how it goes!