Reciting tashahhud behind the Imaam

Q: When your praying namaz behind the Imam, in every salah in the final rakat when you are seated in tashahhud, the minimum you have to recite is the tashahhud dua and if you start reciting durood and the Imam does salam then you have to do salam as well whether you have finished reciting the durood and dua or not, is this true? And in Zuhr, Asar, Maghrib and Esha, after the second rakat when you are seated in tashahhud and you are reciting the tashahhud dua, if you havn't finished reciting the dua and the Imam stands up for the 3rd rakat, do you finish reciting the dua and then stand up or do you follow the Imam and stand up even if you haven't finished reciting the tashahhud dua?

Attending a shia marriage

Q: A cousin of mine in a highly deendar environment has married a shia and our family decided not to attend the marriage of our cousin. However, a few of our deendar relative and elders called us and scolded us for doing Qata' Rahmi. Q.1 What is the fatwa on attending a marriage/nikah being arranged by Shia? Is it permissible or impermissible? Q.2 Is it Qata' Rahmi on our part to boycott the marriage?

Not going to one's sister in-law's house due to abuse

Q: I am a married woman and I am having problems with my sister in-law. She is very sharp tongued and never misses an opportunity to say rude things to me. I am not a person who can fight back at her as this is not in my nature because of this I suffer emotionally and mentally for a long time due to the things she says to me. Will I be sinful if I stop going to her house as she always seems to have a problem with me? I will not prevent my husband from going.

Zina before nikaah

Q: When I met my wife and asked her hand in marriage, she agreed but we committed zina before she introduced me to her parents and before we were joined together. She was pregnant when we were joined together. What is the status of our marriage and the first child? When is marriage said to have taken place in Islam or when are the two lawful to have sex?