I don't think "[T]heir effects and interactions can be meaningfully applied in explanations" is a good way of determining if something is "fundamental" or not: that description applies pretty nicely to aerodynamics, but aerodynamics is certainly not at the bottom of its chain of reductionism. I think maybe that's the "fundamental" you're going for: the maximum level of reductionism, the turtle at the bottom of the pile.

Anyways: (relativistic) gravity is generally thought not to be a fundamental, because it doesn't mesh with our current quantum theory; hence the search for a Grand Unified Whatsit. Given that gravity, an incredibly well-studied and well-understood force, is at most questionably a fundamental thingie, I think you've got quite a hill to climb before you can say that about consciousness, which is a far slipperier and more data-lacking subject.