Simple answer is yes it can be done.Each watchout display is capable of eight channels of output.
Audio synch between displays is very good, but not phase accurate perfect.
With the way you have split up your audio,
that should not be an issue however.
As for the motu, you need to test that with your hardware setup.
We do have customers who use Firewire motu boxes,
but your results may vary as your hardware is not identical to those who report success.
There is no provision in WATCHOUT for output of either MTC or SMPTE.(WATCHOUT does read and synch to all forms of SMPTE.)
Many users simply drop a wav file of SMPTE timecode on the timeline
to send SMPTE from WATCHOUT using the standard audio outputs.
WATCHOUT will keep the .wav file in synch with the content, even
during editing while jumping around.