Be careful what you wish for. If you don't have any previous large parrot experience you are in for a rude awakening. Cockatoos don't do well in any kind of cage that is not measured in feet/meters. They need an "environment". The cage is just a place sleep and call home base.
No such thing in my opinion. One off the biggest mistakes you can make is getting a baby bird (because I'm going to do it right from the beginning). You are going to be a great mom. This bird is going to love you.
At about 5-7 years old this cockatoo is going to turn into an adult. Hormones are going to start to dictate this birds behaviour. It's going to want a mate (new blood). You as "mom" are not mate worthy. All of a sudden this bird does not like you anymore and takes a keen interest in a friend/spouse/acquaintance and choose them as a mate. This is a very common scenario. There is no harder bird to look after than a cockatoo.
An adult bird that chooses you is a relationship that will not change and you will have the best success with. This is where exposure to these birds in a place like a rescue will be invaluable to you. If you're serious volunteer at a rescue and get some hands on with these birds. You might change your mind about getting one. Please don't shop. Adopt.
Some insightful reading for you.