Keeping silent to avoid an argument

Q: If a mother in law discusses something with her daughter in law and later her son confronts his wife in front of his mother demanding to know what the mother said, the wife remains silent out of respect for the mother in law and also to prevent an argument from taking place between the mother and son. The husband later accuses his wife of being disrespectful for not telling him despite her explaining her reasoning. He still won't see things from her perspective. Please advise if she was disrespectful towards her husband and what should she do if faced with a similar situation in the future?

N.B. The husband never admits to being wrong and cannot be reasoned with.

Mispronouncing letters in salaah

Q: In sanna, instead of saying "Wata Baarakas mooka" I recited "Wata baarakas buka".

In Surah Ikhlaas instead of saying "QulhuwAllah" I recited "QulhuAllah".

In attahiyyaat I didn't pronounce the ha sound from throat.

Instead of pronouncing مُقِيمَ الصَّلَاةِ I pronounced "muqeemus salati".

In the tasbeeh of rukoo and sajdah I said "rabbial" instead of "rabbiyal" (I added yal instead of al) and I didn't pronounce the ha sound of these tasbeehaat from the throat.

I made all these mistakes without knowing it and I have made these mistakes in all my previous prayer since I started. Do I have to repeat all those prayers? 

Remaining silent in order to avoid fights

Q: I would like to know the ruling on remaining silent to avoid conflict with family members and my mother.

1. Whenever I say anything it's always used against me so I would like to know if I remain silent and just greet would that be permissible?

2. My mother curses me while angry and I don't want this to happen. Please advice.

3. My mother always questions why I go for Umrah because of 1 bad character trait which I have. Which is remaining silent when angry... her anger stems whenever I ask her to join me for Umrah. I thought that taking one's parent for Umrah is meritorious... Am I wrong in requesting this? Please advice on duas for family unity.

What is considered as Hawaaij-e-asliyyah?

Q: A person has only R1000 in cash but he has 7 cars. He uses one every day of the week.

Does he have to pay sadaqatul fitr, make Qurbani, and cannot receive zakaat because of these cars? He is using them however.

In Behishti Zewar the same type of thing is mentioned for furniture and clothing etc., that as long as he is using the clothes and furniture it will be considered to be from his needs. Does it matter if he has 100 pairs of clothing and 100 cupboards, 10 cars, but uses them? Will this still be considered as his needs, and thus can still accept zakaat? Or do we look at the fact that he only needs one car actually, thus the rest will be above his basic needs.

This would then mean we would have to say the same for clothing and furniture. Or is it correct to say that as long as he uses the items regularly then they will be classified as his needs, no matter how many cars etc he has. If so, How regularly would he need to use the items?