I am not sure why the spokes broke (rear wheel btw), but because of the coaster brake, I probably didn't realize the first spoke at first, and kept riding it until 3 spokes had to be replaced. The LBS told me that it probably was potholes etc. which could be, I also load up my bike quite a bit.

The pedal vibrations are hard to explain, but it's pretty much that. Let me clarify, it only occurs when I am coasting. I am wondering if something is rubbing (I don't hear anything, though) I do think it has something to do with the work they did on the coaster brakes. Is it possible that this is just something that can happen when new brake pads are installed.