Haha. Hairpulling seems to be a natural part of the procedure for a project like this!
For the water you do have quite a few options. If you don’t have any scenes where the surface of the water is actually broken (as in the entire animation takes place underwater), you could easily get away with some kind of overlay in your preferred compositing app, or using a depth channel, you could create a fog and tweak the settings to look like water.
If there is a scene where the surface is broken, you could create a “splash” blendshape on a dense plain or something like that. Regardless I wouldn’t worry about it too much. There are lots of options for faking it. Personally I would go for the depth channel/motion graphics. Even though after effects can be slow, It would still be days faster than rendering out all that water. Yikes!