1) A girl was pregnant before marriage. Later, she married a man who got her pregnant or another man. Can the baby be given the 'bin' / 'binti' to the husband?
Based on the books of Fiqh and Islamic Laws by Dr. Wahbah al-Zuhaili pg 855 Volume VII:
“If the child was born less than six months to two Lahzah (seconds), then all the ulamak agreed it is not the husband’s lineage and it is proof that the pregnancy occurred before marriage, except if the husband claimed that the baby was his child, assuming that the woman got pregnant before marriage, either an invalid(fasid) aqad or by syubhah intercourse. .”
The baby can be given ‘bin / binti’ to her husband if the baby is born after 6 months 2 Lahzah (seconds) after their wedding date.
2) I want to marry a widower. My mother does not object, but my brothers and sisters disapprove due to the slander and false accusations from his former wife. My siblings and I are not on speaking terms due to this.
You can get married and if your family can’t accept it, they can take their grouses to court.
3) I've divorced my wife and we’ve reconciled and remarry. After that, I divorced her again. Then, my wife complained to the court and we reconciled. After that, I had pronounced talak(divorce) dua in front of a Shariah court judge although I’ve divorced her for the third time.
If the final pronouncement uttered is only as an explanation to the court about the utterance of the 2nd, then the final divorce does not occur at that point. But if he intends to divorce his wife then talak tiga(final divorce) occurs.
4) I was married witnessed by witnesses brought by the representative of the Wali Hakim. After a while, I found out, one of the witnesses had committed incest. What is my marital status?
Based on the books of Fiqh and Islamic Jurisprudence by Dr. Wahba Zuhayli pg. 855 Volume VII:
“Fair it may seem on appearance: people who are straight and honest and religious, be it from appearance, as long as fasik act is not committed and does not deviate from the true teachings of Islam.”
The marriage is valid(sah). The witness viable physical. Whai is known after marriage does not affect the marriage and whatever the witness did is between him and Allah and nobody knew of the witness’s behavior before the aqad.