By advanced training, I mean empty its bowels and urethra before leaving home so it can't mess the street; never threaten strangers while walking unless directed by the owners; and when directed to continue onwards, when sniffing something etc., actually starts walking immediately- how long would a dog school allow for such training?
Well, it depends.
It will depend on the race of the dog, some learn quicker, some are more obedient, some can be more difficult to train, on the "character" of the dog.
On the character and discipline of the owner, wether the owner has previous experience with a dog or not, how much time you are spending with your dog and on the training.
It will also depend on the law in your jurisdiction, for some or all dogs training may be required.
Generally, the dog will "go" when you go on a walk, I do not know anybody who trains there dog to use the toilet, although it is possible.
You can expect good results after 1-2 years and daily training.
Which type of dog do you want? Do you have a race in mind? Do you have family, children? Do you live in the city/country? Have you taken a dog from a shelter for a few days?
When a dog goes out for a walk, it should be considered his time. This should be a happy time for them. You should NEVER try to train a dog NOT TO GO to the bathroom. It seem to me that the dog has no happy play time, everything is discipline. For myself, my dogs are just like my kids: you love them, they love back.
You seem a bit young/naive: how do you know that you are training this dog right? Did you go to school or are you guessing?
Some dogs have been inbred (meaning that someone has allowed a sister and brother to have babies) and won't be as smart. It's just like people: members of the same family shouldn't have kids because of increased likelihood of genetic defects. If the dog has been inbred, the dog just won't get it. All the training in the world will not help that dog. Dogs are not these super-smart, stand-at-attention, do-what-I-say-and-when dogs. Dogs are loving creatures. If you treat them to be bad to people, then they will be bad. Treat them with love and kindness, and they will love you until they die.
Some people think they can make a dog learn by jerking them around by the neck. Their necks are just like yours! They don't have this super-strong neck that you can jerk around. If you are loving and kind, they will usually do what you say to love you back. Maybe you aren't ready for a dog.