Useful co-sleeping tip #8: Introduce change slowly.
When moving kids from one sleeping location to another, we did everything gradually. We started to talk to our eldest about moving into her own room months before we officially did it. She slept in there a couple times before the official switch but she still preferred the toddler bed so we didn't make a fuss. Everyone was sleeping well in our bedroom Pangaea. Suddenly, our eldest was playing with her dolls and talking about how the big kid doll was ready to sleep in her own room, so we struck while the iron was hot and she moved into her own room that night. The princess sheets which my forward-thinking wife had purchased made the change special. There have been no complaints so far, except from us.
While the eldest was ready for the change, the little one was not quite ready for the toddler bed so the change was made even more gradual for her. First, she dozed next to me in our bed. Then I placed her in the toddler bed and she cuddle against my arm. I extracted my arm to whimpering which was calmed by a hand on her tummy. Finally I snuck out of the room, as slowly as a tectonic plate, so that I could avoid the squeaky floorboards.