Just in general, I guess I'll add some things here to think about when it comes to creating characters for this. 

What kind of person would seek out a place so isolated from everything they've ever known? 

What kind of person would leave behind everything, in search of a place that may not amount to much more than myth? 

Were they seeking Aeredal, or did they happen on it by chance? Characters could be one or the other. Aeredal is not widely known, the merchants bring goods twice a year, but strangely do not speak much of it when they leave. *spooky music*

Wars, conflicts, the daily grind of peasant life, exist outside of Aeredal. Aeredal itself will present it's own challenges, but there is no need to create a "special" character - perhaps they are running from something, but they could just as easily have been a farmer or a soldier, a disinherited fourth son or priestess.