I'd say Quirrel was trying to kill Harry with the dementor. He only warned about the wand after Hermione was about to go before the dementor and discover it anyway.
Sense of doom comes from 2 voldemorts(or horcruxes) being dangerously in sync. (Voldy marked harry as his equal ie made him Voldemort)
Father's bones are buried inside Bella? That's twisted but so is Voldemort.