I found a wonderful place for a house, the only flaw is, there are predators spawning in that cell (LvlAnimalForestPredator) from two LLMarkers.
I did what worked without problems in Oblivion: Draw the markers down under ground and set "initially disabled". The creature markers are attached to three X-Markerheading, which I all disabled too.
Nevertheless, when I enter that cell, the creatures are present where the markers were and attack. I even checked ?starts dead“ but nothing helped. I tested with two different clean saves directly out of Helgen.
In the cell nearby there are two skeletons (EncSkeleton01Melee1H, not the LL-Markers), which I disabled too and there it works.

Any suggestions? I want to keep that location for my new house and it seems I have to advise the users to disable the creatures via console.

Did you disable the creatures themselves, or just the markers? If the latter, do the former.

Also, to more rapidly test your mods, you can use coc commands directly from the main menu rather than starting a new game and waiting through Helgen's destruction. You'll start with a basic character that looks like the one from the trailers to Skyrim.