Hey!
I happen to have knowledge on this because I called yesterday and asked "How did I get my role?"
(I'm very unhappy with my role as QSFB, so I figured if I couldn't change it, I at least wanted to know why I got it so I could have a little closure.)
I called and asked "Why did I get this role? I know I checked it off as a possibility, but in my phone interview, I wasn't asked about this, yet I was asked about all the other roles I checked off." The recruiter said it was because some roles have role-specific questions and others, such as QSFB don't. It is more of a general thing for most roles actually I think she said. So if you get asked questions in detail about a certain role, don't expect to get it and vice versa if you don't get asked questions, you could still possibly get that role.
She went on to further explain that I got my role as QSFB because of my limited work experience. Currently I'm a nanny so I thought that would show a high level of responsibility and they wouldn't judge so harshly. I was extremely disappointed with the way the recruiter answered my question. She made it sound like I was only capable of working QSFB. I genuinely thought the CP wouldn't be based off of work experience, but maybe other things like passion for the role. Example, I don't know how anyone would have "attractions" experience, so how do those people get their roles? I don't have any food experience so why did I get my role necessarily? It all seems a bit skewed to me just because everything at Disney is so much different from the real world anyway. Yes, someone may have retail experience, but I think WDW stores are a lot different. Maybe someone who knows every store well and all the merchandise should get that role, like me?

End rant. Sorry that came off like a lot of complaining, but that's my experience with finding out how you get your role.