It's all about the characters and the setting

I'm getting my ideas together on what to do with these 3rd graders. (Am I putting more time and thought into this than it needs? Probably. Welcome to my life.) I want their 'take home' message to be this: characters and setting are the basic ingredients for the fiction stories they want to write.
So, what I'm thinking right now is to have them choose a card that has a character on it, like a little brother, a rock star, a carpenter, or a monster/creature they create. They have to define what that character looks like, how they behave, what they like to eat, and in general, create the character from the ground up. Second, they'll choose a card with a setting on it, like a Wild West town, a cave, an island, or the Space Shuttle. They'll have to draw a map of the setting or list physical attributes like buildings, mountains, electronic devices, and whatnot. Third, their 8 or 9 year old selves have to meet that character in that setting. How they each got there, how they interact, what they say to each other, and what they do together is an instant plot. What do you think?