There are a few things we must understand before I go into my theory:
1) Aurash is who Oryx was before the pact was made with the worms that turned her, her sisters, and their followers into the Hive. It is also worth clarifying for future reference that Aurash was female.
2) Aurash CAN be simulated by the Vex, whereas the darkness within Oryx prevents them from producing a 1:1 simulation of him.
3) Simulations produced within the Infinite Forest CAN leave the Infinite Forest. This is proven both by how we can get loot from the forest, and how Osiris and Sagira are genuinely concerned about the Cabal getting out in one of the Mercury Strikes.
4) The reason the Hive are so obsessed with killing is because of the worms that they have a symbiotic relationship with. Their worms hunger for death, and so they do too. If a Hive does not satisfy its worm's hunger, they will be consumed by it.
5) Aurash is not Hive, thus she does not have a worm. For that reason, she would not be nearly as hostile towards guardians and the light than her present-day incarnation or any of his followers. Furthermore, when she was simulated by the Vex and brought face to face with Oryx, she was horrified by what she saw.
6) The Infinite Forest is capable of simulating things that existed even before it did. This is proven due to the simulation of Mercury's past.
7) The Infinite Forest is capable of simulating places and events that had nothing to do with Mercury. This is proven because Osiris and Sagira have visited a simulation of the Hive Homeworld, Fundament.
[b]My theory is as follows:[/b]
Aurash could return via the Infinite Forest and become a potential ally.