Hi,

Is hard to tell without diving into the scene, but the interpolation looks correct to me. It will depend on the algorithm that you are using though. I would like to see the Hairs from Guides results without any modifier above. If the interpolation changes suddenly or after reloading the scene, maybe the morpher is changing the topology or tessellation of the mesh at loading time. I need to check the scene to know for sure. 

Regarding the workflow, I think the best approach is to have multiple hair systems for each hair tyle: Mane, short fur, wiskers, ears, inner ear, etc... This allows for better control and less complex hair stacks. Also is better for debugging. 

Jeordanis Figuereo (Product Designer. EPHERE Inc.)