My Animation Narrative Goals

I want to be able to create and construct a character which is fitting with the narrative and has the capability to make an emotional connection with the audience
I have looked into many well-known and some not so well-known fables and how they are constructed, I decided after reading through these that I didn’t want my story to have such a defining moral throughout that it didn’t let my imagination run wild when coming up with a concept. For example, I didn’t want to have to base my entire narrative on a moral/saying such as ‘Don’t judge a book by it’s cover’ but explore a wider area of messages and meanings.
I want to set my animation in post-apocalyptic Japan, many many years in the future the world has changed and technology was only getting stronger. However ‘something has happened’ which appears to have wiped out the majority of the human race and all of the technology.
The story now centres around a young girl, finding her way in this exotic and new landscape. We aren’t sure how long she’s been alone fending for herself but we get easter eggs from the way she’s dressed and when she’s hunting for items.
I want the story to show how a young human being, nature and technology can all come together as one and live amongst eachother instead of eradicating ‘the enemy’.
I was thinking design and narrative wise I would really like to have hidden easter eggs throughout this animation (dramatic irony). For example like the idea of having posters maybe war propaganda, tanks etc. Left around the world, overgrown with foliage.