Which character traits make Fortunato such an easy target for Montresor in"The Cask of Amontillado"?

The character in Poe's "The Cask of Amontillado" with the
ironical name of Fortunato is the possessor of personality traits that are, indeed, his
nemesis.  In fact, he is easily duped because of these
faults:

1. He imbibes so much that he is incapable
   of logical reasoning and clear perception.   When, for example, Montresor takes him
   farther and farther into the catacombs, the drunken Fortunato does not stop to wonder
   why they are proceeding so far.


2. He is vain,
   believing  himself a great connossieur of wine, one whose opinion should be valued over
   that of others. 


3. He is petty.  Fortunato does not want
   anyone to taste the Amontillado because he wants to be the one to judge it and take
   credit for having done so. Determined to not let his rival Luchesi taste the wine before
   he does, Fortunato becomes myopic in his thoughts as he risks his health in the damp
   catacombs filled with miter just to prevent Luchesi from tasting the
   Amontillado.


4. He is deluded in his judgment of Montresor,
   suspecting no ulterior motives from a competitor.  As a result, he is easy prey for his
   enemy who lures him deeper and deeper into the catacombs of his family.  When Montresor
   protests, Fortunato foolishly takes Montresor literally, saying that he is fine and
   there is no need to call Luchesi--"[he]is an ignormamus"--and is totally stunned when
   Montresor walls him in.