I would not be able to confirm about any of the specifics about getting on and off the cruise since i haven't boarded a cruise from Panama. Regard taxis/cabs, they will be avaiable at all touristy spots you may go to, Casco Viejo, the Causway, Miraflores, the airport etc. They are also available along the street wherever you want and see one. However some may want to charge you extra for being tourists. Overall they are a valid option but I'd keep Uber open as an option as they are pretty cheap here compared to in the US and the prices are confirmed by you, not them.