When I've made coffee beers, I've always steeped the coffee grounds in the wort just after I kill the heat. Coffee connoisseurs will tell you that "a coffee boiled is a coffee spoiled..." so I wouldn't add the grounds to the boil. I would imagine that you could brew the coffee beforehand and add that to the secondary, but I don't have experience with that. I've had good results with just putting the grounds in a hop sock and dropping it in the wort after the boil ends and let it steep for several minutes.
As far as the chocolate, I would add it to the boil within the last 5-10 minutes. I've only used cocoa powder and never chocolate itself, but I imagine it's the same principle.
1. Dubbel 2. Oatmeal Amber 3. Ger Pils 4. Pale Ale 5.[Nitrogen] Dry Stout
1. Pils 2. Pils 3. none 4. none 5. none 6. none
1. Brett Ale 2. Lambic 3. Lambic 4. none
About 36 gallons of beer & 4.2 gallons of mead
Kegged & conditioning:
Oatmeal Amber Ale, Camp Beer, Bourbon Barrel Imperial Oatmeal Stout