We had one like this as an option on one of our SACs but I decided to choose a different one.
This is just how I do things so you don't have to take all of this in. I personally wouldn't break them down into characters, I'd probably go through a more specific group of ideas that you can take directly from the question.
Meryl fears being stuck in her own job and life and not accomplishing anything.
Just touching on the imaginary fears, a good suggestion I heard was that you should definitely talk about how imaginary fears are no lesser than the 'real' fears because they are all real fears. Irrational fears are different to imaginary fears.
Anna seems to have a fear being trapped in a life that she cannot get out of, ie with a child. She wants to be young, travel and meet better people than let's say Andy (sorry Andy).
I hope some of that helps, as I said it's all just suggestions so good luck!