Dumbledore is not dead.

Well just about everyone I know who read Harry Potter have one opinion or another about what is going to happen in the last book.

I believe that Albus Dumbledore is not dead. He either drank Polyjuice Potion and swopped appearance with either Aberforth or Snape, or (since we now know that there is an opposite of a horcrux) transfered his death into this thing.

1) Why was there always a character close to Harry killed since the second book?
I think this is to make the reader believe that Albus is really dead.

2) Would Albus ever plea to another wizard not to attack him?
Nope

3) Why did Aberforth met with Mundungus? to exchange goods?
The necklace around Harry's neck on the cover perhaps?
Will this contain Albus' life or death?

4) Why would Albus who is one of the greatest wizards have such a rather pathetic brother?
Well might just be that he have a greater part to play.

5) Why did Albus always trusted Snape?
Albus was clever enough to know who trust and who not to trust.

One thing I'll bet on is that we'll learn more from Aberforth in this coming book.
I do hope that my other prediction that Dumbledore is not dead is also correct.