You're 150lbs and you're trying to lose weight still..... huh???? First off, you cannot gain muscle and lose fat at the same time, in order to gain muscle/weight you need to be in a calorie surplus, to lose fat/weight you need to be in a defecit, since you can't do both of those at one time you have to pick one or the other.
Aside from that you have two problems, 1) if you're trying to lose fat, you can't get much lower than 8% which you say you are and maintain that for very long, its not healthy. 2) You want to build muscle and not gain fat, with muscle gains are going to come fat gains, its unavoidable unless you're building muscle over years at a snails pace.
To your original question, progressive increasing weights creates a stimulus for growth, providing your body with a calorie surplus will then give it muscle gain. The protein is just that, protein, it won't help you build any different muscle than eating chicken would. The only difference in protein powders are amount of servings, amount per serving, protein type (different proteins absorb at different rates, ex: whey - quick absorbing, cassein - slow absorbing), extra carbs, sweetners, etc. So if you need extra protein in your diet, just get the cheapest whey you find, use it postworkout and any other time when you're not getting a sufficient amount, but don't rely on it, whole foods are better overall sources of protein.
So get your goals sorted, then lift hard and eat accordingly, GL.
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