Dumbledore has done an Obi-Wan

. He'll guide Harry through the currents and torrents of finding the hoarcrux pieces one by one. Whether in spirit or in person I doubt very much that his legacy is over quite yet

. Dead he may or may not be. While the reasoning is valid, your premises that Snape didn't actually turn evil is as yet unproved, though I think Dumbledore's trust in him wasn't misplaced as Harry so dearly believes

.