Unfortunately whey protein comes from milk and as a result many of the negative effects of milk come with it. It will contain the "naturally" occurring hormones that are contained in milk. Milk is engineered by cows to grow baby cattle into 1000 ib creature in less than a year, so in terms of weight loss I doubt it will be much of an aide. If you are looking to increase protein then eat lots of greens and quinoa. If you feel that you absolutely need to supplement protein for some reason then I would use a vegan protein which typically come from rice, hemp, pea and spirulina (I don't personally use any of those).
Under no circumstance what so ever should a healthy adult expect to experience muscle gain on 1500 calories a day unless you are already a very petite woman (like under 100 ibs). If you are only eating fruits and vegetables and lead and active lifestyle then 2500 for women, and 3000 for men are good minimum numbers. Keep your fats relatively low, get most of your calories from carbs.
*Depending on what your current diet is like you may also experience a great deal of "detox" (rashes, feeling cold, diarrhea, head aches, feeling cold) symptoms in trying something like what you've outlined above. If you lose more than a pound in a week it's typically either (in this order) muscle, water or waste. Fortunately detoxing would involve weight lose from waste. Track your workouts though, if your first couple of lifts are going down then you are likely loosing muscle. After those first couple lifts, if you are in a calorie defecate then those lifts should be expected to go down.
In regards to your workout program there isn't enough data to give a response. Depending on the volume of work done in those work outs that could either be under training, or epic over training.
Sorry if I'm kind of being a debbie downer. Someone else may have more positive feedback, but those are my opinions.