Professor Severus Snape & Lord VoldemortvsProfessor Dumbledore & Professor McGonagall

Professor Severus Snape & Lord Voldemort Voldemort and Dumbledore stalemated in their short duel. I do believe Dumbledore would win though. Snape matched McGonagall in their duel. Minerva was trying to kill Snape, while Snape wasn't even using powerful spells that he has mastered like Sectumsempra. Snape would defeat Minerva.

Professor Severus Snape & Lord Voldemort Snape defeats McGonagall before Dumbledore and Voldemort finish their duel. Snape then helps Voldemort defeat Dumbledore.