You can still bake your shadows per frame so it will work fine.

Displacement will work fine for this, it doesnt matter what kind of shadows your using, bump maps will do nothing with your shadows. Raytracing requires geometry to calculate, bump maps just create normals based on a height map that it generates from the texture, a normal is just a vector direction.

With raytracing, no geometry means no calculation, scatter some random objects on the floor with dynamics, or use a rough displacement, you can always convert your displacement onto a high res mesh to save the time of it calculating every frame.

The closest thing to what you are describing is steep parallax mapping,

You can use a parallax mapping shader which can do self shadowing this will query the current sample on a surface and look up linked lights to decide to self shadow or not. Again this works best for facades and it cannot calculate other objects since it just queries its own height field to calculate the shadows.