There are several systems also known as Traditions within Wicca, a few of them are:
Alexandrian
Gardenarian
Dianic
Faery
Seax
Blue Star
British Traditional
Eclectic
Each tradition has it's own set ways for ritual, entrance, and teaching into the craft, however the one thing that unites them is their devotion, and the common poem known as the Wiccan Rede which states "An it harm none, Do what thou will".
Yes, Wicca does exist. Wicca is a pagan revivalist religion that incorporates many ancient Celtic traditions with other pagan pantheons.
ancient pagan traditions
There are many different "Traditions" of Wicca, including but not limited to, Gardnerian, Alexandrian, Dianic, Norse, Celtic/Druid, and Faerie.
There are many books and magazines by Wiccans and about Wicca and Wiccan traditions widely available in bookstores and online. But because Wicca has no central organization or hierarchy, there are no official publications.
As Wicca is a religion focusing not on race, but on the belief structures of the individual, there is not (to my knowledge) a specific African-American Wicca. If you are asking if there is a participation by African-Americans in wicca, then the answer is yes.
You mean the Faery Star, or Eleven Star. The Elven Star, or seven-pointed star, is found in some branches of the Faerie tradition of Wicca and sometimes in other Traditions as well. It is a reminder that seven is a sacred number in many magical traditions -- it is connected with the seven days of the week, the seven pillars of wisdom, and many other magical theories. It is used in many magickal Traditions, not just Wicca. Really, that's about all I can reveal about it, without getting some magickal practicioners riled up... the deeper "true" meanings are still (somewhat) held in secrecy...
This question has never truly been answered. Many people believe the first organized modern practice of Wicca was started by Alyester Crowly. But the ideals of Wicca and the traditions date back much further. They go back to some of the first civilizations. Celtics, Druids, Greeks, Native Americans, Norse, and Inca all have had the same common practices related to Wicca today. Wicca is a diverse religion with no real 'right' or 'wrong'. So in many ways the person who follows the religion creates their entirely own practice. Many modern Wiccans do not even associate themselves with Alyester Crowly or even the first societies who shared the same traditions. It truly depends on the individual person as to the opinion on where Wicca originated.
It depends on which nation you're talking about. You need to be more specific.
Tribal traditions differ as do traditions of sub-tribes and whanau (family). To be able to answer appropriately, please be a little more specific in your question. Are you asking for protocols (tikanga) or kawa (customs) or general family traditions?
Due to that area's specific religious traditions.
Wicca is a newer religion based on a mix of Saxon/Celtic folk traditions and Ceremonial magic. It was officially called Wicca by Gerald Gardener in the 50's. In the United States, Wicca was finally recognized as a religion in various states and by the Army in response to it's soldiers wanting to practice their faith without persecution.
Because the vast majority of Wiccans are not involved in secret rites, there is not much about Wicca that oath-breakers can reveal. Some Wiccan traditions have some practitioners who find secret rituals meaningful. Supposed revelations may refer to fairly common knowledge that certain Wiccan rites reflect their founder's background in the Masonic fraternities.