How does active later (i.e. ontime activation) and deactive later (i.e. offtime deactivation) behave in CQ 5.2.1?
Activating later starts a workflow to activate the current version of the page at a specified time. The only indication that the page will be activated later is the item in the workflow.
Deactivate later is not available in the default 5.2.1 installation; however, it's available in 5.3.
As long as the item is in the workflow, then it will be activated when this workflow is processed even if that page does not existed in the publish instance. For information on active or deactivate later for CQ 5.3, please review the documentation here.