The Chinese company should have the following documents:
1. Company Registration Certificate
2. Export License
3. Factory Registration Certificate
For Banking documents,ask for Certified copy of audited balance sheet of last year.
There`s very few english resources to verify Chinese companies.You can trying searching the Chinese yellow pages at
http://www.yp.net.cn/english/search/searchForm.asp
The whois information for a website should be registered to the company name.
You can also hire
www.sgs.com to do a factory inspection to verify the company.
Scott