While you are able to blend Shading Models using the BlendMaterialAttributes node, you’re not blending actual materials. The Blend Mode is excluded, and as far as I understand this has technical reasons. In this specific case you would need to render the hair cards twice, once using deferred rendering (the masked blend mode) as well as forward rendering (the translucent blend mode).
This probably also means that you would run into the same problems you’re trying to avoid, due to the different rendering techniques the blend modes use.