Fridge Brilliance: Harry is given the option at King's Cross of dying. While this would have been sad if he would have taken this route, things were still set up for Voldemort's defeat anyway. Harry would have been proven actually dead by Bellatrix, Hagrid still would have carried really-dead Harry back - but nothing that happens would have stood in the way of Neville destroying Nagini - the final Horcrux - and thus someone being able to take out Voldemort (though probably at the risk of even more casualties), even on the off chance Harry's death had made Voldemort the master of the Elder Wand.
Considering Harry still would have sacrificed himself for them Voldemort's enemies still would have been protected from his magic and he'd be trapped on Hogwarts grounds, his minions beaten and surrounded by everyone who wants him dead without any Horcruxes to save him. Voldemort was pretty much dead the moment Harry decided to go to him.
Fridge Brilliance: Of course Voldemort never noticed the resurrection stone had special properties - even if he turned the stone three times to activate it, Voldemort had no departed loved ones to appear.
Fridge Brilliance: Once again, it was a mother's love that saved Harry from Voldemort.