I also have Cockatoos and Amazons, all of my Amazons are female though. What Melissa said about Amazons being laid back and not expecting a whole lot out of you is mostly true! We have a rehomed BFA female who is in love with my significant other, Jon, and puts up with me. BFAs are one of the hot three and the males can get really feisty. Iris can be a brat to me sometimes as I am not her chosen person. She likes to headbutt me if I'm in range of her and she'll pull on my pigtail if she can get to it when I'm feeding the birds and I'm not paying attention. She will step up for me though and is, in general, a pretty good bird and very funny. She's also in love with my YHA, Amarillo, so she definitely isn't going anywhere!
I have Galahs and a totally plucked D2 who wouldn't dream of going after anyone because he couldn't defend himself. The Galahs pretty much don't care about the Amazons for the most part. My youngest female might try to start something with Iris every now and then, but they're both fully flighted and evenly matched, so it never lasts long and I don't worry about it. Iris is more apt to go after other birds to be honest with you...she can be a little pit bull. I also have greys and she's gone after them and takes great pride in just bullying my TAG who is a bully himself. I can't let the two of them out together. Even caging Iris and letting Tuchis out isn't a solution unless I put Iris in another room or take Tuchis to a different room because Tuchis will bully Iris from outside the cage.
Every bird is an individual though and you never know what you will get. I think you've got a better chance with a female BFA and how you raise her will make a difference too. I also think knowing her personality right away will give you some indication up front. When I got Tuchis as a baby, he was feisty even then!
I don't know what Iris was like as a baby, so I have no insight there. I do love her even though she can be a brat though!
And like John said, just having a second bird around can be helpful because they do like the company even if they don't get along. Hope any of this helps!