Etiquettes

Q: What does "was-salaam" mean? Is it Sunnah to end a letter with these words? Is it compulsory for the person who receives a letter which ends with "was-salaam" to audibly reply with wa alaykum salaam?

Q: When I meet my Aunt (father's sister) do I need to bow my head in meeting her or can I just make Salaam from a distance?

Q: If a man greets a woman, is it assalamu alykum or it is assalamu alyka?

Q: On the day of jumuah I told my friend jumuah mubarak. He said there is no hadith to say Jumuah mubaarak. If we say jumuah mubaarak to someone is it wrong?

Q: Please advise if a niece is allowed to shake hands with her uncles (mums brothers) and clarify all who are allowed or not allowed?

Q: Is it kufr to end a letter with "regards"?

Q: Please explain the severity of writing Salams, Slmz, Salam Alaykum, Slms etc instead of writing Assalamu Alaykum. People think it's no big deal when you tell them. From a scholarly point of view please elaborate why these abbreviations and versions of conveying Salam are incorrect?

Q: When a man makes salam to a woman, should he say assalamu alykum or assalamu alyka?

Q: Is it right to say "Jumah Mubarak"?

Q: What is the correct way of greeting? Assalamu alaikum or Salam alaikum or Assalam alaikum?