240-250lb body weight is too heavy post NLP for your situation. The length of your NLP will vary, but it certainly won't last long enough to get you to that body weight, with a body composition you'd be happy with. You'll want to get to 170lbs as soon as possible and then add 2lbs+ of body weight per week from there. As you advance into the intermediate stage and you become a lifter, you'll decide how much more weight you want to gain. The rate of weight gain will slow down since the rate of your progress slows as you move along in your progression as a lifter. Get through the NLP and make damn sure "inadequate weight gain" isn't the factor that causes your LP to end. It's very unlikely that you'll gain more weight than you want to during this stage, provided your programming is correct - and even then, 100lbs of weight gain is really not possible or desirable in that short of a time period. You may want to be 5'9" and 250lbs body weight, but with a 600lb deadlift instead of a 365lb deadlift.
Goal number one is to hit the protein target. If that requires whey supplementation, fine. Work towards getting all of your protein from whole food, but if that's not possible due to time/money/convenience constraints, whey will suffice. Drink it with whole milk.
The main benefit of having a protein heavy breakfast is to ensure that you start the day on the right track and are more likely to hit your goal. The reality is, all meals need to be protein heavy to eat enough for this program.
I don't have enough practical experience with this sort of stuff and don't want to parrot "common knowledge." I'll ask one of the nutrition coaches from SS Gyms to comment. Santana would have great input here too.