If you have enough, dye it! The fullness of what you have nearly doubles!
Seriously, it makes a huge difference and the cost is minimal.
Dying your hair increases the volume due to the chemical reaction. The hair follicle expands and becomes thicker. Changing to lighter or darker doesn't really matter though bleaching causes the most thickening inmy experience.
You won't lose hair unless you greatly over do it. Most preparations are pretty mild.
That's good advice and some people definitely over do it. I saw great results and wanted to throw it out there in case it helped some of the fellas here.
That's a good question. I've never seen any.
Straightening my hair made me feel fine with my current level of male pattern baldness, but it was a bit of a combover.