re. 2: Not many, according to the sources I can find on that. Example: "[M]uscle tissue has been observed to burn roughly seven to 10 calories per pound per day, compared to two to three calories per pound per day for fat. Therefore, if you replace a pound of fat with a pound of muscle, you can expect to burn only approximately four to six more calories a day."

Source: http://www.acefitness.org/fitnessqanda/fitnessqanda_display....