Someone need to update this page with the other possibility, in which neither Malady or Jahan is present in the Black House.
I think that if you learned the way to the Nameless Isle, so that Malady doesn't have to make a pact, she won't be present. If you manages to kill the Advocate, therefore cleaning up the Bloodmoon Isle, Malady also doesn't have to make a pact (or couldn't), so she won't be present.
If you don't learn the name of the demon from the tree, Jahan wouldn't know about his true name, and didn't entrust the task of killing Adramalikh to you, so he didn't get captured. If you managed to convince Jahan as well, he won't be in the prison as well.
At any rate, that was the thing i did, and neither of the two is present at the house