Though I have never personally owned any species of Amazon, I have worked at an Avian and Reptile Rescue for 8 years now, and worked with many, many different Amazon species, from the smallest to the largest, and what you need to really understand and take to heart is basically what Sailboat said to you in the very first reply: You need to allow whatever parrot you bring home, regardless of species, to choose you...
I cannot stress enough to you how each and every individual bird is completely different than the next, very much in the way that human-beings are. I would not even dare to make ANY broad generalizations about the differences in personalities between a BFA and a YCA, as it's so difficult, almost impossible to generalize their personalities at all. The minute that someone tells you that "A BFA's personality is like this..." or "A YCA's personality is like this...", and then you adopt one and bring it home, i can guarantee you that the bird you bring home will be nothing at all like what was described to you...
***The advantage that you gain when you adopt an adult parrot is that you get to spend a lot of time with the bird, and you actually get to see what their personality is like, what their behavior is like, and most-importantly you get to see whether or not each individual parrot you are spending time with connects with you personally, or "chooses" you. You can't really do this when you bring home a very young baby parrot from a breeder...
So the best advice that anyone can give you is to not worry about what the "general personality" of a certain Amazon species, or any species of parrot is like, and to certainly not make ANY decisions about what bird to adopt based on these types of generalizations. Instead, when deciding what parrot it is that you adopt, you should keep a totally open-mind about what particular species it is that you want to adopt, and just go and spend a good amount of time with each individual parrot that is available to you for adoption...And then you should not only see what individual bird you connect with, but more-importantly what bird CHOOSES YOU. And if that bird doesn't happen to be an Amazon species that you had considered prior to meeting the bird, keep an open-mind to that, because the species isn't what is most important when choosing a bird to adopt as a companion/family member. What is most important is the bond that the bird is going to have with you, and vice-versa.
