No it will only hydrate you if it is in pure water form. The water in milk (it's mostly water, like all beverages) simply vanishes in your stomach once the proteins, sugars and fats have all been digested.
That just means that you're focusing too much on arms. I'm not sure a full-body workout is the answer.
Problems I see with your routine -
Squats 3 times a week? Ouch.
You are doing both flat and incline 2x/week but all you're doing for shoulders is military 1x/week. You're neglecting...
Eat more. It is that simple.
If you couldn't gain muscle (but were gaining weight, i.e. fat) then it might be more complicated.
But if you're not gaining weight period then you're simply not eating enough. 3500 calories is now your maintenance intake. Eat more to gain.
Most people will increase protein and possibly carb intake while bulking on-cycle, because the gear will repartition nutrients to muscle (thus inhibiting fat gain to some degree).
While cutting it depends, but some people actually eat less on-cycle than off on the theory that the steroids will...
It's weird because at TP the prices per pound are:
egg white protein = $10.79
WPI cold-filtered = $9.29
WPI micro-filtered = $9.59
WPI ion = $9.89
WPC = $5.89
So egg is almost double WPC, but barely more expensive than WPI. But yet egg products cost at least 2-3x more than whey mixes...
MT is VERY overpriced, and many of their supplements are junk in the sense that they deliver only mild benefits but claim huge benefits...
But they're certainly not dangerous, and some of them do work well (although not better than similar supps at 1/3 the price). So if you got them for free...