First I gotta say, that is beautiful! The whole setup is amazing and you have some lucky ducks...
I *think* the lines might be ok for the hawks issue, but owls are definitely a different story... I really don't know if the lights themselves will be an effective deterrent due to their night sight, it may interfere enough, but I'm just not sure... I do know that they are much more analytical in their approach to prey... we had owl issues here ourselves... they would land on top of the chicken coops to study for for prey, figured this out by finding owl pellets left there...
Our grow out pen and our Calls we put plastic netting over... might not be much, but it has kept them out... found a pellet on top of the grow out netting once right after it was put up... the only time we had an issue with the netting was in one pen where we had our Araucanas, they were awful about perching on top of their coop at night... we put netting over and it walked across it until it dipped enough to trap one and it ripped through to that bird... we raised the netting and the Araucanas decided to sleep inside their coop after that and haven't had issues since...
So... maybe add at least a plastic netting across the top? And I really would think about the anti-perch strips... hope this helps...