In the end, It's implied that they would be sent back to other planets..
Some of them would get to stay though.. The main character ends up in a human body after abandoning her current host so that the host could have her body back. She was gonna do the whole "Noble Sacrifice" thing.
But... The humans had gotten attached to her, so they found a human who's mind was practically non-existent for her to use as a host.
“She'd become a governess. It was one of the few jobs a known lady could do. And she'd taken to it well. She'd sworn that if she did indeed ever find herself dancing on rooftops with chimney sweeps she'd beat herself to death with her own umbrella.”
― Hogfather