Is writing down a list of marital movables a right for the wife in Islamic law, and is the husband sinful if he writes it down despite his family's objection?

Reducing the dowry and marriage expenses is an indication of the woman's and the marriage's blessedness, as the Prophet, peace and blessings be upon him, said: "The most blessed of women are those with the least burden (expenses)," and "The most blessed of marriages are those with the least burden (expenses)."

There is no upper limit for the dowry, as Allah Almighty says: "But if you want to replace one wife with another and you have given one of them a qintar [a great amount of wealth], do not take anything back from it."

The bride's family is permitted to stipulate whatever they wish, and if you agree to their demands, you cannot retract unless they consent. Your agreement without consulting your family is not a sin, but it is better to consult them if you know they would be displeased.