It seems like one of those areas that you may have to experiment with. I would do test with small batches of less expensive beans until you feel you perfected the right temperature, smoke flavor, and smoke time. Experimenting may cost you a lot of bisquettes, but at least you will not be experimenting with expensive beans.
Cold smoking (90°F or lower) may very well work, since most coffee beans are slightly oily. But you may want to try higher temperatures since more chemical reactions occur the higher temperature you go. Maybe try a batch at 100°F - 180°F, for shorter time periods.
Mesquite is a strong flavor for the Bradley. My go to flavor is pecan when I'm smoking anything from the plant family; either vegetable or fruit.