From what you have stated it suggests to me that, perhaps, you are taking the 'non-fiction' elements a bit too far. Are you reproducing the entire newspaper/magazine article? If that is the case I'd focus on the actual story first and then weave in snippets and small segments from the other sources that are perhaps much more concentrated on how they relate to the story. ?
This is stupid - but bear with me! - say your protagonists have to go to a deserted fairground/carnival ('cause they need something there but it's being guarded by a horrible monster of some sort) then perhaps you could start it with a paragraph from an old flyer when the carnival was actually working - describing it, making 'ironic' comparisons of the fun visitors will have there, compared to the experience that your characters are actually going to have at it??? Anyway just the first thought that came to mind.
There have been a few novels I've read that are a bit weird in mixing non-fiction-type writing with the prose...unfortunately I can't remember the name of the main one that reminds me of what you've said
I really liked David Zindell's
Neverness because it had a smaller form of this - with a quote of sorts to start each chapter from various sources. It's probably a bit pretentious now, but I was only about 17 at the time when I read it and I was even nerdier than I am now
Dracula isn't quite the same as it's mostly diary entries and letters from the main protagonists to each other, so it all drives the story forward (although I have to admit I found it a bit of a dull Victorian melodrama, too many ladies swooning and men vowing to forever defend etc...)
On an unrelated note, I utterly loved the way that stories and lore would come out at you unstructured in the game Oblivion/Skyrim - as it was all in short pieces in in-game books and they tended to come at you randomly.