45-60 mins MAX
Yes but you should bleach it first.
You can leave bleach on the hair for up to an hour. After this it will not work. You have to make a fresh batch. The more time that the bleach is out in the air the less time you have to put it on the hair. The ends are dark because there is more of a build up of colour there. You will have to do this on a few separate occasions. Because your hair is black the bleach will take longer to take the colour out. Black changes to red, the orange then blonde, it does take longer to get black out.
Depends on the bleach, how much colour is on the hair etc. Probably around 40 minutes, you will probably need to tone the highlights and you'll DEFINITELY need to keep checking. For a caramel you should lift your hair to an orange-yellow colour, then tone.
Most likely, if you used dye, it stands on the package
Yes, you can, but you will probably need 40 Volume Bleach. It is very strong and will probably leave the extensions fried afterwards. Remember to deep condition them if they are real human hair.
You should bleach it first. Well, it really depends on what color you want it, but usually you bleach it. I don't recommend bleaching black hair though, because bleach damages black hair more than any other color. You may never get it back to your natural color.
long hair
3hours
no, it won't bleach your hair but it will dry it out!
It certainly does.
Bleach
You don't. Bleach is incredibly harmful for your hair. Shave it off and get a wig intead.