Mistake in Attahiyyaat and Durood-e-Ebrahim

Q:

1. If one happens to omits portion of Durood Ibraaheem due to one forgetting it or making a mistake, is the Salaah valid?

2. If one happens to recite Tashahud and one repeats the portion( Ash Hadu...) where the index finger should be raised, perhaps due to getting stuck, should one raised the finger twice?

3. If yes, and it was not raised twice, is the Salaah valid?

4. Whilst in Salaah, during Durood Ibraaheem, one adds the words "Sayyidina" before the words and Names Muhammed (Sallallahu Alaihi Wassallam) and Ibraaheem (Alayhis Salaam), is the Salaah valid?

Mocking and ridiculing people

Q: Person A tells Person B the following joke. He says the memon was in Jahannam when he met his friend. His friend said to him that you were so pious, how did you end up here? The memon replied that I have a place in Jannah, but I put my house in Jannah on rent. Person B laughed at the joke. I am aware that in Surah Tauba that there is a verse which speaks about joking about Allah and his signs and this leading one to come out of the fold of Islaam. In the scenario presented above, do both A and B lose their Imaan and in the process invalidate their Nikah?

Fulfilling the obligation one owes towards one's mother and wife

Q: I am the only child of my mother, married with two kids alhamdulillah. But recently things are not going well for me. I'm not in a position to provide for my mother and wife at the same time and this is eating me up. I understand very well both have rights upon me but my earnings are very little! It's like choosing my wife over my mother.

Limbs of wudhu shining with radiance

Q: In these Ahaadith:

Abu Hurairah (May Allah be pleased with him) reported: The Messenger of Allah sal Allahu alayhi wa sallam went to the (Baqi`) cemetery and said, “May you be secured from punishment, O dwellers of abode of the believers! We, if Allah wills, will follow you. I wish we see my brothers.” The Companions said, “O Messenger of Allah! Are not we your brothers?” He said, “You are my Companions, but my brothers are those who have not come into the world yet.” They said; “O Messenger of Allah! How will you recognize those of your Ummah who are not born yet?” He said, “Say, if a man has white-footed horses with white foreheads among horses which are pure black, will he not recognize his own horses?” They said; “Certainly, O Messenger of Allah!” He said, “They (my followers) will come with bright faces and white limbs because of Wudu’; and I will arrive at the Haud (Al-Kauthar) ahead of them.” [Muslim]

and this: “On the Day of Resurrection, my followers (or Ummah) will be summoned ‘Al-Ghurr Al-Muhajjalun‘ from the traces of Wudu’.” [Al-Bukhari and Muslim]

In these hadith, it says limbs will be shining white on the day of judgement. In an earlier hadith, you say that people will be white in complexion in jannah? I was wondering, does this mean people will be white in complexion on the day of judgement or just simply shine due to the light?