Snape redeems himself to help Ginny escape Hogwarts.
During "Frame up" Chip was never caught so Tony went to prison for the murder of the woman and others before being sentenced to death. When he finds his 'death' was faked he must trust those who turned on him to keep him safe and find the real killer before he's found and really put to death.
When Diane dies everyone who knows him learns of Tony's connection to her. No one guessed it or saw it coming but her death hits him just as hard as the others.
Instead of a howler when Ron and Harry drove Arthur's car to Hogwarts Arthur and Molly went to pick up Ron from school. Afraid of the consequences Ron runs away from home. When he finally returns he's banned from having any contact with the Weasley's even those at Hogwarts and tries to get through the year on his own. A/U written a long time ago but updated.
When Ellie tells Tony about her childhood and what she associate with them Tony realizes something. Her story and memories point to her being Kelly Gibbs. Tony doesn't know what to do with this news when tragedy hits the family leaving him no choice but to spill the beans.