1.
Charity Burbage (Muggle studies teacher at hogwarts)--Killed by Voldemort in the opening chapter.
Hedwig--hit by a killing curse as Harry and Hagrid are trying to escape some death eaters on the flying motorbike. They and the others (Ron, Hermione, Fleur, Fred, George, and Mundungus took polyjuice potion to look like harry and act as decoys. Each one was accompanied by someone else: Tonks, Lupin, Mad-eye, Bill, Kingsley and Mr. Weasley. 4 of the pairs travelled on brooms, and 2 on thestrals.) were ambushed when they were moving harry away from privet drive.
Mad-Eye--Mundungus (who he was travelling with on a broom) got scared and disapparated, and Mad-eye was hit with a killing curse.
Rufus Scrimgeour--Killed when Voldemort subtly took over the ministry. He was replaced by Pius Thicknesse, who is under the imperius curse.
Gregorovitch (wand maker, the one that made Krum's wand)--Killed by Voldemort for not giving him information on a legendary wand of extreme power.
Bathilda Bagshot (she wrote "a history of magic")--We don't know exactly how she died but it's probable that Voldemort killed her. Her body was used as a disguise for Nagini to lead Harry into a trap.
Ted Tonks (Nymphadora's dad)--Killed by people hunting for muggle-borns and blood traitors.
Gornuk (a goblin)--Killed by same people as above, also someone else was killed but i don't remember their name.
Pettigrew--Tries to strangle Harry but is unable because of his life debt. Because of this he ends up getting strangled by his own silver hand.
Grindelwald (the wizard that Dumbledore is famous for defeating)--Killed in the prison where he is staying by Voldemort
Dobby--comes to save Harry, Ron, Hermione and also Luna, Griphook (a goblin) and Ollivander, they are trapped in the Malfoy's mansion. Just before he disapparates he is hit in the chest by a knife that Bellatrix throws at him. :'(
Crabbe--Casts some dark magic fire spell in the RoR and it gets out of control and kills him. Harry is able to rescue Malfoy and Goyle though.
Fred :'(--Killed in an explosion created by a death eater during the Battle at Hogwarts
Tonks and Lupin--Killed during the Battle by unknown death eaters...we only learn of their deaths when Harry does.
Colin Creevey--same as above. is found outside the castle, dead.
Snape--KBitten by Nagini on Voldemort's orders. more explanation why in my answer to no. 2.
Nagini--Decapitated with Griffindor's sword by Neville ^^. He pulls the sword out of the (burning) sorting hat that Voldemort made him wear to torture him, turns around, and slices the snake's head off ^^
Dolohov (death eater)--Killed by Prof. Flitwick lol.
Bellatrix--casts a killing curse that misses Ginny by an inch; Mrs. Weasley gets REALLY mad and yells a lot while she duels with her, finally killing her with an unnamed spell that slams Bellatrix right in the chest XD yay!
Voldemort--Avada Kedavra rebounds on himself (for the second time...)
2. Okay, so the "Deathly hallows" are three objects that are said to be able to conquer death. Harry's invisibility cloak is one, the Guant's ring is another, and the third one is a very powerful wand, called the Elder Wand or the Deathstick.
The true ownership of the wand can only pass from person to person if one succeeds in defeating (disarming counts) the previous owner. Dumbledore obtained it when he defeated Grindelwald.
Now, when Dumbledore was killed, remember that Malfoy disarmed him with expelliarmus. Than Snape came in and killed him. (Snape is good by the way, he had agreed with Dumbledore to kill him if nessecary, because Dumbledore was going to die soon anyway because of the curse that was put on the ring horcrux.)
-Another important point is that when Harry is trapped at the Malfoy's mansion, he disarms Draco. This makes HARRY the true master of the Elder Wand.
Voldemort then takes the wand from Dumbledore's tomb, but it never works correctly for him. He finally figures out that it is because he never defeated Dumbeldore himself. He than assumes then that Snape is the owner, and kills snape in order to gain ownership.
Harry watches as Snape is killed (snape and voldemort were in the shrieking shack when it happened, and harry was in the enterance) and when voldemort leaves he goes in and is there when snape actually dies. Snape gives Harry his memories, and harry puts then in a silver flask that Hermione congures.
They go to Dumbledore's office to look at the memories, and Harry discovers that Snape is on the good side and that he loved Lily his entire life. He also sees a memory where Dumbledore tells snape to let Harry know that Harry was accidentally made into a Horcrux.
Harry realizes that he has to die for voldemort to die, and goes to let himself be killed. (even though one other horcrux is left besides himself--Nagini) Voldemort "kills" him and Harry is in this place full of mist that looks like king's cross station and Dumbledore is there and talks to him, explaining that Harry is not actually dead yet, he can choose to die or go back, and that the peice of Voldemort's soul that was in him was destroyed, so he is no longer a horcrux. What's left of Voldemort's soul is also there, a miserable creature huddled under a seat. Harry decides to go back instead of "going on" and returns to his body.
Meanwhile, Voldemort had also passed out, his death eaters were worried he was dead, (something to do with the fact that Voldemort had used Harry's blood to ressurect himself) but when Harry comes back Voldemort gets up too. Narcissa is sent to check if Harry is dead, she lies and says he is, and Voldemort goes back to the castle and shows everyone that harry is dead.
During the distraction caused by Neville killing Nagini, Harry pulls the invisibility cloak on top of himself and watches as the death eaters are defeated one by one, as house-elves, order members, teachers, students, and other creatures band together. When Molly kills Bellatrix Voldemort is furious and is about to kill her, but Harry casts a shield charm to protect her, and takes off the invisibility cloak.
Harry taunts Voldemort in front of everyone in the great hall, informing him that Snape was on the good side all along, and calls him Tom Riddle, which of course makes Voldemort very angry. He also explains that Snape was never master of the Elder wand, that Malfoy actually was:
"But you're too late," said Harry. "You've missed your chance. I got there first. I overpowered Draco weeks ago. I tok this wand from him"
Harry twitched the hawthorn wand, and he felt the eyes of everyone in the Hall upon it.
"So it all comes down to this, doesn't it?" whispered Harry. "Does the [Elder] wand in your hand know its last master was Disarmed? Because if it does...I am the true master of the Elder Wand."
[Harry Potter and the Deathly Hallows, pg. 595]
Voldemort gets really mad, and shouts Avada Kedavra, and Harry casts expelliarmus. But the Elder wand refuses to kill its own master, and the curse rebounds on Voldemort, killing him once and for all, his Horcruxes having all been destroyed. The Elder Wand flies through the air towards Harry and he catches it.
3. Not too interesting actually, but here it is: It's right before they find and destroy the 3rd last horcrux (Harry and Nagini are still left) and the Battle at Hogwarts is starting.
"Hang on a moment!" said Ron sharply. "We've forgotten someone!"
"Who?" asked Hermione.
"The house-elves, they'll all be down in the kitchen, won't they?"
"You mean we ought to get them fighting?" asked Harry.
"No," said Ron seriously, "I mean we should tell them to get out. We don't want any more Dobbys, do we? We can't order them to die for us --"
There was a clatter as the Basilik fangs [Ron and Hermione got them from the chamber of secrets and used them to destroy the cup horcrux] cascaded out of Hermione's arms. Running at Ron, she kissed him full on the mouth. Ron threw away the fangs and broomstick he was holding and responed with such enthuiasm that he lifted Hermione off her feet.
"Is this the moment?" Harry asked weakly, and when nothing happened except that Ron and Hermione gripped each other still more firmly and swayed on the spot, he raised his voice. "OI! There's a war going on here!"
Ron and Hermione broke apart, their arms still around each other.
"I know, mate," said Ron, who looked as though he had recently been hit on the back of the head by a bludger, "so it's now or never, isn't it?"
"Never mind that, what about the Horcrux?" Harry shouted. "D'you think you could just -- just hold it in until we've got the diadem?"
"Yeah -- right -- sorry --" said Ron, and he and Hermione set about gathering up fangs, both pink in the face.
[Harry Potter and the Deathly Hallows, pg. 502-503]
There ya go! =)