Does divorce take place by the husband joking that he did not accept at the time of nikaah?

Q:

1. At the time of nikaah the husband said qubool and the witnesses heard it. Few years later, the wife asked her husband if he said qubool in the nikaah? The husband said "no". He said “no” jokingly and had no intention of divorce. Is there any problem?

2. If a divorce thought comes in the mind when touching a kinaya word of divorce, is there any problem? The husband did not utter the word, he just touched the word with his finger. 

Divorce letter not reaching the wife

Q: I wrote a divorce letter to my wife and signed it in the presence of a qazi and two persons. The qazi was about to send the letter within the next 3 days. I did it because she was caught red handed talking closely to a stranger over the phone. She was pregnant at that moment.

After two days, I thought I will give her one more chance to correct herself and stopped the letter and the letter was destroyed. I also informed the two persons that were present when I signed the letter and I started living with her. She gave birth to a baby girl one month ago.

I thought it was necessary to deliver the letter to her for the divorce to be effective. She still does not know about the letter.

Recently I asked an Imaam about it and he said that the divorce has occured even though my wife was not present and the evidence was destroyed.

My question is, is my marriage still valid? 

Marrying a girl without her father's permission

Q: I used to talk to a girl from my relatives. We decided to get married. At that time the girl lived at her grandfather’s house. I went there several times. The grandfather and the girl told me that the girl’s father gave the girl’s grandfather permission for her to get married. In 2017 nikaah was performed. Mehr was decided, witness were present, ijaab and qabool took place and the khutbah of nikaah was performed. The girls parents did not know about the nikaah.

Once nikaah was done, we meet twice and we were alone in the house. Now I want to complete the rukshati. I want to know if this nikaah is valid or not? 

Forgetting to recite sunnah qiraat in salaah

Q:

1. Before starting witr, I made an intention in my mind that I will recite the surahs which are sunnah to recite in witr. Then I said softly that I make niyyah to pray 3 rakat witr, but I did not say anything about which surah I will recite. During the prayer, I forgot to recite the sunnah surahs in the first two rakahs. Then I thought that I will do sajdah sahw, but I forgot to do that too. Is my witr valid?

2. Is sajdah sahw waajib if someone intends to recite a specific surah and then forgets to recite it?