I wish to find out the visa requirements for my Chinese wife and Children.

I find the requirements for tourist type.
1. passport with the validity of six months at least.
2. recent six months color photos in white background. Its size should be 35X45mm
3. filled application form
4. copies of the Chinese ID card (front and back side on the same paper)
5. copy of your wife's company's business license
6. a letter from her company that approves her leaves for Cameroon. It must has the company's stampe and manager's signature.
7. round-trip air tickets, bank statement and yellow card

I personally think that you may find an agency to help you deal with it. It costs some money. But they can process your application quickly.