- Do I need to send LTC to the two boards to synchronize them?
- Can I route the audio from the 1º board (i.e. aes channels 1..4) to all inputs, to have the same reference audio in all video streams?
We generally use the "-mc" option to use a single LTC feed and that seems to work fine. In fact, i think you need to use that option with 2-channel boards as there is only one LTC input.
There is no facility for routing audio as you describe.