Joining on the train of skyrim's ostricised. Exactly saame isssue: no scene fire-ups, no merchant barter dialogue options (except for the court wizard), with exactly the same LOOT-tweaked load order it suddenly works on new game allright (though it didn't work on my main save since right when I started it, but back then I thought it's just what one quest mod did. Spoiler - it was not that mod's doing) But for me it's in Whiterun.