Certain “realistic” water effects are unlikely to emerge until Forward shading is added to the engine. There are two plugins that support tesselation:
And one of the developers, , is developing a hair as well: Hair Rendering Simulation test - Game Development - Epic Developer Community Forums
Hair has always been a very, very painstaking task in game development, and good results can still be had with normal methods: here’s a good thread that covers the basics - Realistic hair in unreal 4? - Community & Industry Discussion - Epic Developer Community Forums