No you have to trade for them, there are no scheduled events pertaining to Celebi or the Shiny Trio. Most if not all of them ended in February and earlier March.
The only Mall Tour ones left are Arizona Mills in Tempe, AZ & Orange Park Mall in Orange Park, FL. That end 3-19/3-20. So if the OP lives in those areas then that is about the only way.
Brian - 0089 1621 6313 - White