Give them emotional depth - and remember experiences can make folk bitter as well as courageous. Jenny, for example, is at loggerheads with her mother and is likely to remain that way for some time until Eileen shows some contrition or Jenny decides to let her grudge go at Eileen for dropping her right in it.
Character versus plot? Plot versus character? It’s like trying to decide whether you need oxygen or not. You need both. Both need to be well thought out. Eileen’s awkwardness helps drive her plot as she makes life damned difficult for herself but she also needs a story to set up those difficulties for her to try and resolve.
Look at motives. Not only can story ideas come from these, they can add emotional depth. Eileen’s chief motive is to stay on earth with her family and never to resume her old life. It colours her attitude, fuels her behaviour and sets up clashes with the Fairy Queen. Are the motives for your characters strong enough? Overwhelm your characters with problems - you get your story from how they cope.