Read it well, some great information in there. Nobody wants to lose hair, there is no way of telling why this happens or if it will happen to you though. It is not something that happens often at all but there is no known way of preventing it either that I know of. The main concensus seems to be that if it does happen the hair will always regrow as well or better than before.
As for putting on muscle mass while fasting. It's possible, it depends on what else your body has to do. If you have a lot of toxic waste to dump in that extra body weight you have you may find that your body simply has more important things to do than grow more muscles. So it depends, if you have bags of energy, go build muslce, if not just rest and do what exercise you can while fasting, then when you finish your fast and refeeding be assured that your muscles will grow back at the best rate possible once you start working out again.