Hi,
To see latest appointment by Customer / Employee you can create a simple report on Data Source - (CODAPAHB )Appointment with key figure as Start date.
This will give you latest appointment by selected Characteristic.
You can achieve similar report on any other data source as long as Date( Start date) as Keyfigure ( given by SAP).
Start Date is not available as Key figure in All Activities data source. So for other activities check at individual data source level for Key figure list whether date is available or not.
Hope it helps..
regards,
Raju