1. SIRIUS BLACK
I cried a lot when Sirius Black died and I am pretty sure so did the others. I personally feel that he should have survived. Even JK Rowling mentioned that she planned on killing Arthur Weasley but had a change of mind in the last minute.
If Sirius would have survived, he would have been a source of comfort for Harry. He would have understood Harry and his decisions. He would have supported him no matter what. After the Battle of Hogwarts, he would have a pleasant but limited relationship with Narcissa as she helped Harry. And who better to tell about James Potter and Lily to Harry’s children. He would have regaled the kids with the antics of marauderers’. He would often get reminded of his friend James when he saw the tricks of James Sirius Potter.
2. SEVERUS SNAPE
We all hated him to the core but the prince’s tale made us fall in love with him a lot that he ended up as the favorite character for the fans. Who would have imagined that we would cry when we would know the truth of one of the hated characters.
If he had survived, all the teachers, students, order members would have respected him a lot and he would be asked to continue as the Headmaster of Hogwarts. He would decline it and as Prof McGonagall to take over. They would share the relationship which Prof Dumbledore and Prof McGonagall shared. Harry would apologize to him and Snape would start loving all students alike. He will be fond of Albus Severus as he also would have lily’s eyes. He would tell the three of them about the life of Lily before Hogwarts. He and Sirius will sort out their differences and be on good terms.
3. REMUS LUPIN
His death didn’t have the impact which the previous characters had but nevertheless, I would have wanted him to survive the battle of Hogwarts. He would have been there for his son guiding him during his growing years. He would miss Tonks terribly and would try to see her in Ted. Hogwarts would have got a permanent defense against dark arts teacher. Snape would still give him the potion during the onset of the full moon. He along with Sirius would still roam around Hogwarts. While Sirius would encourage Harry’s kids to be naughty, Lupin would be there to correct them, give them sound advice.
4. FRED WEASLEY
I really didn’t want anyone from the Weasley family to die, even if one had to, it could have been Percy or Charlie.
If Fred had survived, he along with George would have run their shop successfully. The twins, along with the help of Sirius and Lupin, would come along with other creative ideas. The four of them would lurk around all places and create their own map of all places they visit. George and Fred would teach their children and all their nieces and nephews new trick and they would be the coolest father for their kids and coolest uncle for their nieces and nephews
The fans were shocked when Dobby died. The tissues were all wet, I am pretty sure of that.
Dobby, being a free elf, would often come to Harry’s house to help him but Harry would ask him not to help. He would still help during his absence. When Harry and his family would meet Sirius at his place, he and Kreacher would fight for doing their chores. He would irritate Kreacher but Kreacher would not mind. In fact, Kreacher would become friends with him and Winky. He would also go to meet the Malfoys where Narcissa would treat him kindly but Lucius would still be mad at him.