Do you feel your hair is naturally very strong and thick? If so, it may be able to manage it. My hair is naturally strong and when it was bleached, it wasn't dry or damaged at all; the hairdresser was surprised. I've dyed my hair way too many times and my hair is still fairly healthy. All bleaching will damage your hair to some extent, but it's worse for different hair types. If you get it done professionally, it shouldn't be too damaged, they often put in loads of lotions and potions to protect your hair and to moisturise it.
You will be able to go back to black if you dye it black. However, the bleached areas will show up lighter than the rest so it will look uneven. I'm sure a hairdresser could solve this problem though. You may have to have all of your hair bleached to get it all the same tone underneath before dying back to black to avoid lighter patches.
Dying and bleaching is all bad for your hair. For some people it got so bad they have no choice but to cut it off and let it grow anew. So be careful! To be honest I think it's best to accept your natural hair color, but if you want to experiment... Well you only have one life after all! :D
Basically, any bleaching will damage your hair. Eventually, you'll be able to get it back to black and it'll return to it's normal quality. I recommend using argon oil or macadamia oil. In the past 2 years, mine has gone from a natural dirty blonde colour, to purple, then to bright red, then to bright blue, and then bleache it and turned it to white. It's now slowly becoming my normal blonde colour again. Hair usually does return to it's natural colour, if you let the dye run out and keep trimming the dead ends away and all the hair from underneath.
Yes, of course it will. Bleaching ruins hair - always and for everyone. I think you have to wait a certain period of time before dying your hair again + you'll probably always have a reddish glow to your hair even after you dye it black - you'll only get your actual color when it grows out.