what types of documents needed for applying China visa for family members?

Basic Requirements:
1) Valid passport (at least six months before expiration) with blank visa pages and copy of the first three pages;
2) Typed Visa Application Form (Form V2011A)
3) Applicants who have never been to China before should submit in person.

You need also submit additional documents to apply for an X-visa:
1) an approved Foreign Student Visa Application Form (JW201 or JW202) issued by the Chinese authorized unit or the Ministry of Education
2)Original Admission Notice from universities or colleges in China recognized by Ministry of Education of China and copy
3) Original Visa Application Form V2011B and copy
4) Physical Examination Record from local public hospitals and copy
5) Your passport should be valid at least 13 and a half months

You should submit those additional documents for your kids and relative for applying for dependent-visas to stay with your husband i China:
1) Invitation letter in Chinese language from your husband and six-month bank statement
2) invitation letter from China Foreign Affair Office
3) birth certficate of your two kids and the certificate proving the relationships between your relative and your husband

Even though you submit all the requirments, your kids and relative may get refused to get dependent visas, or only get L-visas or X-visas, whose allowed staying days are shorter.

The embassy will be open in working days, usually Mon-Fri if there is no festivals drop on. There is no need to get a serial in advance.