Voldemort's Ghosts/Priori Incantatem

[zfshiruba]

No: HPFGUIDX 187609

When Voldemort's victims appear in the graveyard due to the brother wand effect, How does Bertha Jorkins know Harry's name? Obviously she'd know who Harry Potter was, but how would she know instantly that the boy she could see was Harry Potter? Do Voldemort's victims haunt him? They aren't actual ghosts, but they seem to be up to speed on events. 

Also, when Priori Incantatem is used on Harry's wand, it shows a ghostly form of the Dark Mark, right? So why do only the Killing Curses come out of Voldemort's wand? Why not a ghostly vision of Harry under the cruciatus or the form of Wormtail's silver hand?

Zfshiruba