We have a PV array installed on our campus, under the same ownership, but not on the building or within the LEED project boundary. Can we count that toward EAc2?

Yes. Provide a letter from the owner allocating some or all of the solar power to this project. Make sure that the solar power allocated to the project is not already allocated to another LEED project, and won't be in the future. Also, be sure that the owner retains ownership of the power and the RECs being generated.