Edgar Allan Poe uses a lot of name symbology in "The Cask of Amontillado" and other stories and poems.  I have pondered the name Luchesi on previous occasions and have never found a language link as far as an actual word meaning.

However, I would propose the following:  Poe used words not just for meaning, but for the way they sounded. Luchesi is actually pronounced Loo KAY zee- with this sound, we can see that maybe Montresor was using the unseen and heard from Luchesi in the story to drive Fortunato crazy (KAY zee) and proof that he himself was a LUnatic.  Keep in mind that we never meet Luchesi, but he is used as the proverbial "carrot on a stick" to lure Fortunato in.