Table of contents: [ Spoiler ] Since this story has grown so much bigger than I ever imagined I feel like its time to borrow a page from some of my favorite SimLit writers and offer you a syn...
What is most important from the start is that you enjoy yourself writing it and are pleased with it. Your audience will enjoy it because your audience is, by definition, people who enjoy your writing. We wouldn't be here reading it if we didn't like it (unless someone is here for an English class studying serialized internet lit :) ).
I could go on a long rambling discussion about different kinds of narrative conflict, and I started to write one, but I'll spare you. I'll just say again that I think your story is great. If you want to bring in new challenges based on serious topics, you can (within the strictures of the forum rules) and I will be interested in reading them... but only do it if it's what you really want to do. If you don't want to do that, you don't have to.