I am still unable to begin the 'Blood on the Ice' questline even after 1.6 promised to fix that problem. After following several guides and comments to attempt to fix the questline, such as reviving all relevant NPCs, entering and exiting Windhelm and another city repeatedly, reseting the questline, setstaging the questline, reseting relevant NPCs, talking to all relevent NPCs, and forcibly entering Hjerim (as well as grabbing up the assorted evidence); none of this has any affect on my broken questline. The reason this is the case, is that I finished all of the Dark Brotherhood questline long before attempting to find this quest. This means Nilsine and Tora Shatter-Shield are both dead in my game, and cannot be revived by any means (since the console will not revive any NPC that dies due to quest-based requirements).

The only way you can fix this problem for PC users is to make those NPCs irrelevant to 'Blood on the Ice', as it is the only variable I could single out in my problems as well as others with the same problem, compared to people who were able to find workarounds for the bug.