The Megan of draft one was seriously underdeveloped. She just followed Jen around, acting timid until about chapter eighteen where she makes an offer ... and then she becomes slightly more developed.
In draft two, however, she really bloomed. She and Jen become instant best friends, and she even stood up to Derek on numerous occasions. As I'm tying up the last few loose ends in Chapter 25 and the Epilogue, she hasn't quite decided about whether or not Derek will make a good brother, but she adores Jen.
With both of Jen's adopted siblings, their backstories were basically nada in draft one. But with two, let's just say that I now know the fate of their parents, and even a few younger siblings. In fact, the pair's backstories ended up being quite vital to the plot. (And I have no idea what I how I got to the end last time without discovering the identity of Megan's dad!)
Unfortunately, their backstories contain plot spoilers, so I can't tell you about them. Popcorn! Derek doesn't even let me say everything I know in the book! (If I ever decide to write a sequel though ... I will pull some people from his past to haunt him.)
Megan is childlike in many ways, her outlook on life, her awe of Jen's imagination, and her faith in Jesus. She loves dragons, especially good dragons, and is disappointed when she finds out that Jen doesn't have any good dragons in her imagination, a problem that Jen promises to rectify when possible.
Let's just say, she has become one of my favorite characters.