She said she's written her last Quidditch match, which would indicate to me that much of the action will be away from Hogwarts. I thought the rubies falling from the Gryfinder hour glass was an elegant metaphore for Hogwarts being wounded, or killed.
I think Dumbledore is really dead. I don't think he comes back as a ghost. Snape was in love with Lily, which has created his love-hate relationship with Harry. Snape gave Voldemort the prophecy information that got Lily killed. Dumbledore was dying anyway, I think for two reasons:
1. The green liquid in the basin was most likely a slow-acting poison. Since Harry gave Dumbledore the green liquid, Snape wouldn't have been protecting Malfoy from being a killer, but Harry.
2. I think Dumbledore was much older than other people think. In the Sorcerer's Stone, he was noted for his work in alchemy with Nicholas Flamel. Flamel was in his 600s, and wasn't noted for any recent work, but he did invent an anti-aging potion. However, he would have had to have done that hundreds of years ago. The last Sorcerer's Stone was destroyed. If Dumbledore worked with Flamel on the anti-aging potion, how old must he have been? If the Stone was destroyed, he would not have any way of making more potion.
For anyone who hasn't read it, here is a link to JKR's interview with Mugglenet and The Leaky Cauldron.
She gives A LOT of information and clears up many things. It is well worth the time to read all three parts.