Yes. On the LS-2, when supplying power to other pedals through the DC OUT jack using a parallel DC cord (such as the PCS-20A), ACA-type and PSA-type BOSS pedals can be mixed.
NOTE: The output current of PSA adaptors varies by model (200 mA or 500 mA). Use a PSA adaptor whose output current exceeds the total current consumption of all connected pedals, including the LS-2 itself. For details on the differences in PSA adaptor output, refer to "BOSS PSA adaptor: Specification Differences by Model".