Doesn't sound very cliche, I've never heard of mythical and supernatural creatures trying to build an underground city to escape humans. Usually its people trying to get away from things like that in stories, not the other way around.
The all species in harmony part doesn't seem all that likely. Like you could throw in something about some of them being enemies with other species but having to begrudgingly work together to survive. Adds some tension.
And if you're worried about all the creatures being too cliche just unravel some of the stereotypical myths about them and make up some of your own. Or play around with the lore of the creatures and have some fun with it.
Like for example the werewolves could be like the vampires pet dogs or something. Or the demons could appear super hellish but actually be nice guys or something, or they are in friendly competition with some angels, instead of being sworn enemies.
The most important thing would be where do you see this story going though?