I have encountered a problem similar to this thread.
Daila is still in Homestead when I reach Mourndale.
I don’t quite remember if I have handed the diary to her before but since she talks about the “writing” and I cannot obtain the diary anymore, I guess I have done so.
I have done the exact same things in normal difficulty (except the Bourbon quest) and she shows up without any problem. And I am not using any merit so I don’t think she is locked behind story progression like the above thread.