I don't think what you want to do is really possible. Seed values for one type of fractal (voronoi in the case of Fake Stones) will have no relation to seed values for another fractal, for one thing. In terms of "following other structure", I think the best you could do might be to use a Warp and use the node that creates the "other structure" as the warper for your new fractal, giving it some semblance of similar form, but still maintaining its unique fractal basis. But even with this approach it is a far, far cry from any workaround for fluid dynamics.
- Oshyan