Everything had been blown out in the open.
Aubrey was Gabriella's true daughter, and her only relation to Ally was that she was Aubrey's "surrogate".
Lyle was a result of Gabriella's anger towards Troy for his neglect and mistreatment towards Talon.
Gabriella was sent back to Earth for the sole purpose of sharing her message with Troy, then she was to stay on Earth until her time. She was the only one in Apex that God believed could warn everyone else. His message was that mass destruction would take place, a new era in time, and that murder would take place across the world in mass numbers. Gabriella's case was the first, and there would be many, many more.
Ally's purpose for killing Gabriella was that she wanted Troy to pay for what he had done to her. Her murder case had been a regular murder case. She had killed Gabriella on purpose. Since Gabriella was sent back down, the gates of hell had been opened, thus causing the worldwide murders to happen. The demons will soon possess whoever they can find, other than Gabriella, Troy, and their three kids, who are protected by God from the madness.
Troy will murder, but it will not be a result of the demons.
The worldwide murder outbreak and the demons are unknown to Gabriella and Troy, and the rest of the world for that matter, but they do know one thing.
The world will soon collapse around them, and only two people can break the spell of the demons.
Troy Bolton and Gabriella Montez.