Yeah, there's a dirt blend shader in there for the interior, but looking back it isn't quite as powerful as I would have liked in the diffuse. I'll definitely go back and improve it :)
perhaps a depth biased blend tied into the opacity nodes? Or actually put a volume actor in your scene where the water is and alter the lighting or fog within the volume
Your meshes overlaps, leading to bleeding and incorrect baking. A way to fix that is you use the matching by names : https://support.allegorithmic.com/documentation/display/SPDOC/Matching+by+name
The dark spots on the metal aren't in your ref, try blending them in more. If you look at the ref the paint is nowhere as dark as under the chipped away labels.
Thanks for the reply Jackablade. This character appealed to me as a "Bioshock" style concept, with a blend of hardsurface and organic modeling. That's the reason I chose this out of a million other concepts :)