Just like the other comments say, it depends on what you want to do with the embellishment and also what shape it is. Flat/thin fondant easily breaks if you apply it to a surface not 100% even, or doesn't lie down smoothly. 3-D figurines will remain kind of soft for several days at the bottom, whereas they are dry on the surface. I would always apply tiny embellishments undried, and let larger ones set for a day or so.
About if people eat them - I'd give a definite no. From my picture cake times I can say that 95% of the fondant I used was either peeled off the cake and thrown away, or kept as a memory of the cake. I have heard rumors about people who actually like the taste of fondant, but I have never met one in person 