A setting like this is pretty easy to free-form as long as people don't go too crazy with it. Fairy Tail actually doesn't have a super coherent story up until after the first time-skip; it's all arc-based, either stemming from the jobs they go on or the characters themselves. So as long as we can create interesting situations for ourselves and no one tries to make a super-big-bad-dark-lord who [i]really[/i] hijacks the story, it should be fine until Vongola returns or the Co-GMs come up with some way to tie things together into a more naturally consistent story.