No to the slippers, not sure about the bathrobes on Celebrity.
Agree on the slippers, we were provided bathrobes on the Zenith in 2005.
Crown Princess March 2017
Explorer of the Seas October 2013
Caribbean Princess July 2006, May 2010 & November 2012
Monarch of the Seas November 2008
Crown Princess November 2007
Celebrity Zenith November 2005
Enchantment of the Seas August 2004