He guessed after Harry told him what happened with the diary. It wasn't confirmed for him until Harry managed to get the real memory from Horace Slughorn. He had a suspicion that Horace Slughorn knew much more about Voldemort than he told and that's why he convinced him to come back to Hogwarts.
No. Albus Dumbledore sees himself reunited with his family, including his imprisoned father and deceased mother and sister.
Albus Dumbledore's brother is Aberforth Dumbledore.
Albus Dumbledore was created in 1997.
Severus Snape used a killing curse on Albus Dumbledore.
No, Albus Dumbledore doesn't smoke a pipe.
Aberforth Dumbledore is his full name. No middle name has ever been mentioned.
Albus Dumbledore was the head of Hogwarts in the Harry Potter series. Lord Voldemort created horcruxes from different objects including a ring. Dumbledore was able to destroy Voldemorts ring by stabbing it with the sword of Gryffindor.
His full name is stated as Albus Percival Wulfric Brian Dumbledore.
Albus Dumbledore did.
Professor Dumbledore's full name is Albus Percival Wulfric Brian Dumbledore
Each of them destroys a Horcrux. (So does Hermione Granger, Vincent Crabbe, Tom Riddle and Neville Longbottom)
Professor Albus Percival Wulfric Brian Dumbledore