No. Baldness is a genetically determined trait (inherited). It is X-linked and so is inherited through the mother.
Having extra protein in your body merely provides a stockpile of fuel/food for potential muscle growth, but you need to work the muscles. Without the work, the extra protein gets you nothing.
Only when they are molting.
yes
Extra protein
If individuals consume protein in excess of the amount needed, the extra protein will not be stored as protein. It will convert to fat and stored as fat.
Extra protein and carbs
no, they were developed by exercise therefore it isn't a genetic trait.
Hemophilia
In real life, yes, a horse at work will need more protein than he will when not at work. Not exactly... You just have to make sure that they are getting the amount of food needed. On Howrse you can't give them 'extra protein'!
The extra amount of protein can either be metabolized, stored as triacylglycerol in the fat stores or excreted by the urine (most likely to happen if your eat more than 3.0 g/day/body weight).
most people use whey protein for weightlifting, however you can use it for any kind of exersize if you need the extra protein