Koel doesn't take kindly to things disrupting her work, so she will be taking on these beasts if they appear. She will make sure that her cooking staff is aware of the dreamcatchers, and will be informing them to arm themselves appropriatey if they can/cannot defend themselves.

While she herself doesn't dream due to her true physiology, she will still be using one as an extra precaution. Ringmaster generally doesn't issue a warning like that without reason!