Mocking someone's beard

Q:

1. I have one uncle whose beard has only few hairs. I had made fun of his beard saying that his beard has few strands of thread... I was actually making fun of his beard, not the sunnah... Also I did not know at that time that we should not make fun of beard... Did I do kufr? If yes, what should I do?

2. Some people call him chinese... did they also do kufr? 

Parents are responsible for their children

Q: Nowadays kids dont tend to listen to parents. They always want it there way either by staying in their own bedroom or come down with the family or even they are meant to be studying but they dont want to and if they do they'll do it when they want even though advising them etc. So in this case what should one as parents do? Do they let them be how they want and just keep advising them. What should be done? Also what should be done if the parents and child argue because of that?

At what age should girl get married?

Q: I am a 19 year old female and would like to know

1. What is the right age for a Muslim women to make nikah?

2. According to the sunnah how should a woman find a spouse?

3. Why do the Ulamaa say its best for a pregnant woman to read Surah Maryam and Surah Yusuf during her pregnancy?

4. What are the benefit of reading those surahs?

5. Are there any ahadith saying that married women should live/stay with their in laws?

Discarding or burning papers that contain the name of Allah Ta'ala, etc.

Q:

1. How should we discard the papers/school books/note books having words written like Allah, Allah's names or ayahs etc.?

2. Which words need to be given respect and removed from before throwing away the books? Are the words Quran, Rasool, Nabi, Muhammad or any Surah's name to be discarded with respect?

3. If we burn them, can the ash be thrown anywhere?

Translating the Hadith incorrectly

Q: I came across a hadith muttafaqun alay about the slandering on Ayesha (Radhiyallahu Anha), after that it was said that the behaviour of Prophet (Sallallahu Alaihi Wasallam) towards Ayesha (Radhiyallahu Anha) changed and he used to say 'how is that one?' which hurts Ayesha (Radhiyallahu Anha) very much, when she didn't know about her accusation.

Can you please explain to me why would Prophet (Sallallahu Alaihi Wasallam) have uttered these statement and what does it really mean? It is confusing me very much.

Marrying one's cousin's son

Q: I am a woman. I have received a marriage proposal from my maternal cousin for his son. My query comes here as I have never considered him with any other feelings except as a son/nephew as he born to my cousins sister. And now my doubt is as I have felt him as my nephew/son, is it permissible for me to marry him? Will my marriage with him be accepted by Allah? Earlier I have considered him as something else, and now I am entering into Nikah with him.