You're 'over-doing' it by asking a bunch of unknowns, almost certain to lack specialist knowledge of this area, about matters that may affect the rest of your life. Stick to specialist medical advice, and accept no substitutes.
The general rule for China is you should have all your home base vaccinations (tetanus, etc.) up to date. You need them at home, and you need them everywhere else, too.
The hepatitis vaccinations spare you the form of which a significant percentage of the Chinese population are carriers, and which is very easily passed on to you through poor hygiene in food handling, for instance. Needless to say, hygiene standards with food handling, although much improved, are not what they might be. The other form of hepatatis is caught in the same way you catch HIV, and so relatively hard to catch. But if you end up in hospital in China for any other reason, your chances of catching it are significant.
If you look into things more closely you'll find the advice for malaria will be that if you are staying in the big cities you mention, malaria prophylaxis is unnecessary. But the recommendations on this change all the time, so don't listen to me, look at CDC and talk to a tropical medicine specialist.
Chances are there will now be postings that say, "Harumph, harumph; load of nonsense. I went to China without doing any of this and I was fine."
Undoubtedly this might be true of any number of people, but it isn't any more relevant than statements such as, "My grandfather smoked 20 day and died quietly in his bed at 94." Smoking nevertheless remains a leading cause of death and no end of nasty diseases, and catching any of the diseases for which vaccinations are being recommended would significantly alter your quality of life, and in some cases shorten it significantly.
In sum: ask the specialist medics, and on the chit-chat boards stick to hotel recommendations and so on, where your life isn't at stake. The good news is you'll only have to have the new Hep A and Hep B jabs once: they last a lifetime.
Peter N-H
China