> I wonder if they can bring the satellite back down, or if the fuels[2] used in the satellite prevent its return.
They can't but not because of the fuels. It's because the Dragon capsule is the only part of the whole launch stack that can re-enter intact, and it's a payload to the rocket. Ther Orbcomm sat is also a payload, but a secondary one. They both get put into their correct orbits (in theory) by the disposable Falcon Upper Stage. There's no way for that Falcon Upper stage to bring anything back, it is just allowed to burn up after it's been used.
They can't but not because of the fuels. It's because the Dragon capsule is the only part of the whole launch stack that can re-enter intact, and it's a payload to the rocket. Ther Orbcomm sat is also a payload, but a secondary one. They both get put into their correct orbits (in theory) by the disposable Falcon Upper Stage. There's no way for that Falcon Upper stage to bring anything back, it is just allowed to burn up after it's been used.