Final Fantasy II = A New Hope
Orphan joins rebel force against evil empire
Firion = Luke (Girly orphan rebel)
The Emperor = The Emperor (obviously)
Dreadnought = Death Star (another obvious)
Leon = Darth Vader (falls to the dark side and tries to usurp the Emperor)
Hilda = Leia (Princess, parents are killed, held hostage on the Dreadnought, must be rescued)
Minwu = Obi-wan (sacrifices himself for more power, Minwu sacrifices himself for the Ultima tome)
Guy = CHEWBACCA
I have always disliked these comparisons, actually.
Firion and Luke are not that close, other than being in a rebellion. Firion was an orphan, Luke was raised by family while not truly being an orphan. We might as well say they match up to Vaan(XII), Tidus(X), Zidane(IX), Cecil(IV), and Luneth(III). Many Final Fantasy leads had parents that died prior to the game or they never really knew.
The emperor is not in A New Hope, nor is their a strong notion that the one in Star Wars might descend into Hell and return with vengeance.
Dreadnought is similar in idea to the Death Star, sure. Without the Dreadnought the other comparisons might never happen, though.
Leon was not Firion's father. Leon did not usurp the emperor, he merely tried to take his place after the emperor was killed by others, but foiled when the emeperor returned from Hell. Vader killed the emperor after turning back to the light side. For Leon it was left ambiguous if he really turned to the light side or just had little choice and felt a duty to his friends... it is also questionable if he was ever really against the emperor in the beginning. Vader also never actually faced the rebellion and worked for them.
Hilda was not held hostage on the Dreadnought, that was an imposter in case she was rescued. Yes, Hilda's parents were killed in the beginning of the game, but Leia's father was Vader.
Minwu fully expected complete death in order to give others the power of the ultima tome, those he had come to trust in the game. ObiWan knew he was going to live on through the force.
Guy ~ Chewbacca is forced. Who represents Han? Guy is slow of speech, Chewbacca seems to say a mouthful throughout the movies, we just don't understand it. They're big and strong, oh boy. Oh, and Guy speaks at least two languages, Chewbacca seems to know only one.
The comparisons are almost entirely superficial and forced. The relation of various events and characters just don't line up to make it as interesting as people like to make it out to be.