No, currently there is no real solution. It's not so much a Hellhound behavior, but the KeeperAI behavior. In the original the AI often failed to handle his units, and often did not know how to assign his units. In KeeperFX he is much more effective with his units, but that of course means that maps designed around the original limitations work not so well.
I am however very open to finding a solution here, and if you have suggestions on how to tweak the behavior of the AI to mimic the original behavior when this is required I would love to hear them.
The AI in FX still casts disease.
You can still select units sorted by level. See here.