The bearer of an 'Edna' fortune, reaps everything written in that note. The problem often is, the implications extrapolate in ways the adventurers wouldn't necessarily predict. Once read, the fortune or saying on that piece of paper, forever alters the time track of that person or creature. The only way to reverse an Edna fortune is to find the Plane's original Dimension it came from, and travel into it. Once there, the story of the fortune has to be figured out in order to be unravelled. It is up to the GM to determine how this is done, but it always involves a lesson of some sort in light of the destiny of the fortune. It is almost always a moral lesson, as the Dimension of Ednas all exist in the moral-metaphysical environment.
The trinkets of the Edna shops do indeed posees magical powers, specifically in terms of the memories of the sellers. Some good, some bad these memories infect the life of the bearer and their timeline often haunted. If the seller had died thereafter, that person's spirit might appear suddenly in the house or living space of the buyer.