In a case like this, what's the best way for the original reporter to track down the center's owner? IMAPS typically shows a mailing address for the owner of a parcel - is there a way to tie that to a phone number?

Generally there is a sign on site for leasing - Sometimes it says "Managed by ___" Sometimes there are for lease signs in unoccupied spaces indicating a leasing agent. That should give you a good start. The owner is often not the active manager.