You might want to fence in an area for them so they don't get in your pool. If you can post a pic we maybe able to give you an idea what breed.I'm not great at maneuvering around on this site so this may not be the place to ask all of my questions. But I will still ask and if anyone knows the answers please chime in.
I will post a photo of my rescue ducks so maybe someone will know what kind they are. Also, when I just had the male (very colorful) he was pretty friendly, even though I couldn't pet him but he would come close and eat from a bowl in my hand. Once I got the female (the brown one) he has became aggressive. He puts he head down almost to ram you. He had hit me hard a couple of times. Why is he doing this now? Also now they are now roaming a lot. They came up to my house today 3 times! And we are on a few acres. I am worried because I have a salt water pool.
As for your drake acting aggressive that is just normal behavior for many drakes Testosterone rules their heads and bodies. If he comes at you like he is going to attack you need to get him on the ground quick, with his head facing away from you I straddle my drake [he is Muscovy and a big boy] I don't sit on him[ I straddle] but I put one hand on his neck and hold him there till he stops fighting to get up. Just like another drake would do to him.I also have to do this with my gander, boy is he something else this time of year. Then when you let him up he is facing away from you if he comes again just keep this up till he finally gives up, But don't expect him to become a placid nice boy over night you'll have to keep this up until He finally gets IT that you are the dominant one in his world.