Agreed a girl is a girl regardless, its the inner workings of the terminology that messes me up most times. Fictional characters though need some hints to know if its your thing or not. Lol you wife is awesome, much respect to you both!None taken and if your brother's GF prefers different terms then those are the terms you should use for her but you should never assume that those terms apply universally; basically go with what the person says and don't question it as there is no good outcome from that.
Luckily, as Syd isn't real it doesn't really matter what you say in regards to her but it's not a bad idea to practice getting it right. My wife calls herself a chick with a dick but she likes to be confrontational