In the exposition to Poe's narrative of fanciful patterns, Montresor, too, establishes a plan of revenge that he states clearly,
- The avenger must punish with impunity
- The wrong is not avenged if the retributions conquer the avenger.
- The redesser must make himself known to the one who has wronged him.
These three conditions are, indeed, met by Montresor in his design of revenge. And, so, perhaps you may wish to mention these in the introduction since it is in meeting these requirements that Montresor manipulates and mocks his victim, and effects his revenge against Fortunato.
Thus, because all Montresor's actions and manipulations--even mockery-- are designed with revenge as the result, it may be better to reword the thesis from that written in the question. That is, you may wish to demonstrate how, through Poe's technique of arabesque (a pattern of returning over and over to the initial disturbing idea) the deceptive concern for Fortunato's health and the grotesqueness of gestures are all part of Montesor's plan of revenge. For, he wishes to conquer the victim and do so without any one learning about it but him. At the same time, however, he wants Fortunato to realize that he is being mocked and victimized. The pattern of revenge that Montresor has set for his victim is paralleled in the labryinth of rooms that victim and avenger pass through in a grotesquely mocking and furtive manner.