

Visiting my brother in Shenzhen? Visa Type, help?
Hi I shall be visiting and staying with my husband in Hong Kong before we both go to stay with my brother who works in Shenzhen. Initially we thought we could visit on a L type, as we are planning to visit China to see and experience the culture, it made sense to stay with my brother whilst there.
Firstly am I right in thinking we cannot apply for the L type, but will need an S2 type?
Secondly, I have not changed my name since married, do my husband and I need to submit a copy of the marriage certificate (issued in Italy) to prove that he is also a relative of my brother?
Finally, What is the official document/stamp that is mentioned? My brother can quite happily send us a letter inviting us over, but that does not look official.
Sorry to make it complicated, but don't want to have trouble on arrival. So looking forward to visiting.