Back to the past

After the war the light side was defeated by the dark lord. Minerva's granddaughter Hermione,Ginny and Luna was the only one left. Minerva died in her granddaughters arm she was killed by Bellatrix Lestrange.

They went to Minerva's office to hide and there was a letter from Minerva and Albus. They used it to go back to the past and save the world. What if they fell in love with the marauders?what if one of them fell in love with Severus Snape? Would they able to save the wizarding world?