I see Joel tried to get you started in another thread that you posted before this one
http://www.backyardaquaponics.com/forum/viewtopic.php?f=45&t=31098&p=573767#p573767.
Sometimes threads just don't get seen by the right people and I'm not sure how many of the Duckaponics people still regularly check the forum. The issues with using warm blooded animals likely kept some people away. For those that don't already know warm blooded animals are likely carriers of human diseases and so it increases the risk if you're growing food for human consumption. The current poster is growing plants for the ducks.
It's tough to say but the proposed system sounds like it would work but keep in mind I've never tried this with ducks. I would change the swirl filter to a Radial Flow Filter since these work better at separating solids . You'll want to figure out what you're doing with the solids from the RFF (or whatever you use), I'd probably compost them, vermicompost them or start a Black Soldier Fly larvae bin. The last two might be another feed source for the ducks depending on what type they are and what they'll eat.
Flow rate through the RFF or swirl filter is important so I would put a T in the line from the pump with a ball valve to adjust the flow. Using a pump isn't as good as having gravity flow from the duck pond because it chops up the solids and they don't settle as well, although, it's easier and should be good enough.
I'm not sure about the smaller filter and how you could work that. You could skim the floating feathers before they get to the pump where they could be a problem. I guess this is another reason to use gravity flow if you can and have the pump come after all the filtration is done, not at the beginning. It would look something like this if you used gravity
duck pond --> RFF --> Grow bed 1 and 2 --> Duckweed --> Sump tank (with pump)
Still might have a problem with the feathers even though the pump is protected this way. Probably have to use bigger pipe and fittings so more expensive. Pump first might be better in this case, I'm not sure.
You might want to contact TCLynx using the Private Message (PM) option of the forum and ask if she'll look at your plan or go to her website and ask some questions
https://www.aquaponiclynx.com/duckaponics-muck. She's pretty sharp and if you're lucky she'll have the time to give you some advice.