Instead of connecting your world displacement and tessellation directly into the final material, plug them into the correct channels of another layer blend node(s), then plug the layer blends into the final material.
I would personally not do it this way though, it would be better to seperate your material layers into their own material functions. (I like to have a genetic ‘Landscape Layer Blender’ material function, that takes in texture inputs and other parameters and output a single final material). Then have a master landscape material that layer blends together as many material functions as you want.
This would give you much more control over each layer and what each layer does / looks like. You could even have two generic material functions, one that uses tessellation, and one that does not.