Is the waiver of the bridal couple concerning the list of movables (dowry items) without the knowledge of her family considered a violation of Islamic law, given that the bride's family stipulates the list for the marriage to be completed, and what is the correct way to waive it according to Islamic law and civil law?

It is permissible for a mature, sane wife to waive her mahr (dower) or gift it to her husband after receiving it. There is no objection to her waiving the list of movable assets, based on the Almighty's saying: "Unless they [the women] pardon" and "But if they, of their own accord, remit to you a portion of it, take it in satisfaction, and enjoy it with good cheer." The waiver is legally valid if the wife pronounces it while she is mature, sane, and acting voluntarily. It is preferable to put this in writing and have witnesses to it.