tricksterpup
It's SPRING!!! BUNNIE RABBITS
Here is what I would do. Paint the walls and ceiling with epoxy paint, and cover the floor with pond liner (basically moisture-proof the room). Build in a vent with a fan on a humidistat to control humidity - not too difficult if the room has an outside wall. I'd lay down some sort of shredded bark on the floor. For the water feature, I'd build a, above-ground pond, basically. Frame up something out of landscaping timbers, and use pond liner inside it. Unless you are on a concrete slab, you will most likely need to do some significant floor reinforcement so this doesn't fall through the floor. Make the pond about 3' deep and maybe 6x6 or 8x8 footprint. I'd built a ledge around the edges of the pond so you had a marginal area that was maybe 1-2" deep where you can put some marginal plants, fill it with rocks for a turtle or some other herps. Find some nice huge planters and get some small trees to plant in there.
I like some of these ideas.. the epoxy paint is a great one but I would remove all the dry wall and use Green board, which is used in Bathrooms. It withstands the humidity and will help prevent Black Mold.
Again, I suggest atleast finding a good carpenter to help you build this, or give you some advice on building it. If you are not a carpenter or into construction, you will need some professional help in the beginning. They can help you design this and look over your plans and ideas for this. They will take out the ideas that will not work and give you some ideas that you may not have thought of.
I am just trying to help save you from some severe headaches down the line in about a year or 2 after this is built.
As for the Permit, you should still check with your city. They may say differently and every city has different rules and regulations.