Hope you're feeling better soon. I wish I were there to help you with this. It's a good thing you're doing, giving them a home. Domestic birds like this often get snagged by fishing lines, attacked by dogs or cats, hit by cars, and left for cold winters without food because they cannot migrate. It's not a pretty picture for them. Adopting them would indeed be a good move. I personally wouldn't worry too much about quarantine because they're in contact with other wild birds; if there was a disease spreading (and there are not many communicable diseases among waterfowl, in all honesty) then you would see dead birds everywhere, as most of these diseases strike hard and fast with high mortality rates. You are probably going to be just fine with these guys. I hope you can find the embden as well, and nothing bad has happened to him/her.