I'm trying to, I'm looking for a way that won't blur the ink
I would have said, maybe to age the pages with tea before hand, but there's no way to do that anymore. But I feel like you still have options.
The BEST one I can think of is to get a medium-dark facial powder and dab LIGHTLY onto the pages. That, or wet a dark tea bag, set it on a plate, take a micro-fiber cloth and dab at it then LIGTHY dab the pages. The last method is to pour cold coffee onto a bowl, and use a cloth to again LIGHTLY dab the paper. If you dab it SUPER DUPER light then the ink won't smear. Test the methods out with different papers so you don't ruin your stuff.
And with the monocle, I recommend buying one off amazon, but for the the total DIY, get a pocket watch, take out all of the mechanics, KEEP GLASS INTACT, and replace the "face" of the watch with a reflective surface, like the shiny side of aluminum foil!
I hope this helps! I know your post did. I'm cosplaying as Mabel next year and I'm remaking the book (She "stole" it from Dipper)
Also, how did you make the ectoplasm?