Good idea though. Having methane oceans like on Saturn's moon Titan would be very ideal for super cold planets and moons. By having water made from other liquids is just a brilliant idea if you want to have flowing liquid oceans on frozen planets.
A chlorine atmosphere would also be a good composition for a green atmosphere, but that's not enough. It is better to have a feature that lets you customize the colors of atmospheres and water just like you customize the colors of a planets surface. That would be amazing. For other types of liquids, other liquids are needed too.