What is the ruling on determining the sex of the baby whether through killing the female spermatozoa, or any other way in order to have a male?
If it is done through having a certain type of food, taking a certain type of medication, or organizing the time of the marital relation, then it is permissible.
Is it permissible for a woman to swear a false oath by the Holy Quran to please her distrustful husband?
It is forbidden for a person to do so since this is considered a false oath (Yamaan Ghamoos) which dips (Yaghmos) its taker in Hellfire if he/she doesn`t seek repentance, and he/she has to expiate for that oath. You should avoid any doubtful acts so that your husband`s chest remains clear from the evil suggestions of the devil.
Islamic creed is a comprehensive creed, and if there is any defect, the creed of the individual or group is not correct. Is the creed of the Sufis correct or not?
Sufism is the practice of applying knowledge; this is how Al-Imam Al-Sha'rani defined it. If some among them have deviations in creed, it is not permissible to generalize this to all Sufis, as there are those among them who are acknowledged by all scholars for their knowledge and virtue. And Allah The Almighty Knows Best.
Is it permissible for a woman who broke fasting due to a delivery to pay a ransom?
She should make up for the missed fasting days once she becomes ritually pure, but it is impermissible for her to pay a ransom while being able to fast.