Salaam & Greeting

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

Q: I could not hear a person clearly on the phone and replied "Wa alaikumus salaam" to the "Hello"/"Good Afternoon" of a non-Muslim. I thought the person may have said "Assalamu Alaikum", but this is not possible. Am I sinful for this? Should I make Taubah and Istighfaar?

Q: What is the ruling of hugging a friend in Islam? If I am a girl and hug my friend who is a girl too is it permissible? What about hugging your friend everyday at the time of meeting and departure?

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: When meeting someone after a long time is it sunnat to embrace / hug one another? Is the sunnat for ones head to go towards the right hand side, what other Sunnats have been mentioned regarding the embrace with regards to hand positions etc?

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