Short answers, pulled from the story.
Faramir is the younger son of Denethor, Steward of Gondor, and the younger brother of Boromir of the Fellowship of the Ring. He appears in The Two Towers and The Return of the King, where he refuses the One Ring, fights in the War of the Ring, succeeds his father as Steward, and marries Éowyn of Rohan.
Yes. Tolkien wrote "As far as any character is 'like me', it is Faramir." His biographer John Garth identified the core parallel: both were soldiers and scholars, and Tolkien gave Faramir his own recurring dream of "darkness unescapable," which Tolkien wrote had been "ever with me" and was even inherited by his son Michael.
Faramir refused the Ring because he understood that using it would mean wielding the weapon of the Dark Lord for personal glory, which he explicitly rejected. Tolkien scholar Elizabeth Solopova links this refusal to the kind of courage described in the Old English poem The Battle of Maldon, a text Tolkien knew well.
Several scholars, including Marjorie Burns and P.N. Harrison, have noted the parallel. Faramir leads his men in green cloaks through the forested land of Ithilien, using guerilla ambush tactics, a bow, and a concealed refuge. Ben Reinhard argues in Mythlore that these details place Faramir firmly in the tradition of the outlaw in the forest rather than the chivalric knight in armor.
No. Christopher Tolkien recorded in The History of The Lord of the Rings that his father had not foreseen Faramir at all, inventing him only at the moment of his appearance in The Two Towers. Tolkien noted that Faramir's introduction postponed the book's ending and spurred further development of the backgrounds for Gondor and Rohan.
In Jackson's film adaptation, Faramir initially decides to bring Frodo, Sam, Gollum, and the Ring to Gondor rather than releasing them, taking them to Osgiliath before freeing them during a Nazgul attack. Jackson explained this by saying he needed a new climax for the second film and argued that a Faramir immune to the Ring's temptation would seem inconsistent to audiences when every other character was tempted by it.