If tested positive, are hotel residents quarantined in their hotels or do they have to/can they go straight home? Will there be a refund from Disney?

If people are staying at Disney hotels, they can go to their hotels and rooms (respecting the barrier measures) and call 112 from the room phone. A specific procedure is in place.
For people not staying at Disney Hotels and for Disney employees (called Cast Members): Advise them to go home as soon as possible (respecting the barrier measures) and call their doctor.