Well let me start off by saying hello, now to your questions:
1) Are these A good or bad group of dogs to have?
The Golden Retriever is an excellent dog to have (from my own experience) as they are loyal, friendly, obedient and submissive etc. The Huskie I do not really know about but I do know quite a lot about American Pit bull Terriers; American Pit bull Terriers have been a banned breed in the UK for a number of years now but they are still in circulation and can be brought fairly easily through the 'Black Dog Market', now, more about the breed, APBT's are extremely good dogs to have if you have the right knowledge on them, for example proper training and socialization is necessary if you are to buy an APBT puppy as they have been bred to be quite dog aggressive especially towards other APBT's. They are very loyal, brave, fearless dogs but they can also be very stubborn, demanding and needy at the same time. Personally I would not buy three dogs at the same time as it would be too much to handle whilst you are trying to train the dogs and you might take out your frustration on the dogs, and thats not fair on them.
2) How hard to get them to be good and obey me ?
It will be extremely easy to get your dogs to obey you if you use the correct tone of voice and training methods for the different personalities of your dog. My Labrador is very food orientated so I can get him to do basically anything I ask by presenting food to him.
3) What to do as an owner to get them to behave and be good dogs individually and as a group ?
As an owner it is your responsibility to protect your dogs even if you do have a APBT etc. The only thing you can really do to make sure they behave in general and in public is to obedience train and take them to puppy socialization classes etc.
4) What to do if the APBT disobeys me as a puppy spank him yell at him etc ?
NO! First of all why are you singling out the Pit bull ? Because what you hear about them in the press ? With any dog you should not hit, spank etc. as this can leave them fearfull of and aggressive towards humans.
5) What should I do as an owner to get them all to grow up and be very nice and obeying dogs ?
Haven't you already asked this question ? Its good to see that your very inquisitive about looking after your dogs but don't you thing 3 is a bit much to begin with. Start off with the Golden Retriever and work you're way up to the Pit bull, I would not recommend you buy a Pit bull until you have read a few books etc. on the breed.
Hope I helped

Sorry for the long answer I just wanted to get my point across. And by the way I am only 14 but that doesn't mean I don't know anything about dogs and there welfare.