Can multiple PWR-01 series units be synchronized to output the sequence waveforms?

Yes, they can be synchronized by using a trigger signal.
Use a branch splitter to distribute TRIG OUT-TRIG IN or cascade connection.
The sequence can be synchronized by applying a trigger signal to the TRIG IN terminal after the sequence is executed by releasing the trigger wait state.
Therefore, it is necessary to execute the sequence in advance and set the trigger wait state by the trigger wait setting of the step.
Alternatively, the sequence can be started by setting the VMCB (multi-channel) function and synchronizing it with GLOB:*TRG from the communication interface.
For the details, read the following manuals:
• the user’s manual – chapter of Advanced Features – Synchronized Operation
• the communication interface manual – chapter of Interface Setup – Multichannel Setup or/and
chapter of Tutorial – Sequence (PROGram).