What is the ruling on writing the name of the husband, "Muhammad"—or "Abdul Rahman" or "Abdul Hakim"—on a gold pendant worn by the wife on her chest, and what is the ruling on wearing it in front of women and entering the restroom with it?

It is permissible for women to wear jewelry bearing common names, even if they coincide with the names of prophets, and it is permissible to enter the bathroom while wearing them. However, if the jewelry includes the names of Allah Almighty (such as: Abdul Rahman, Abdullah) or the names of prophets that clearly refer to them (such as: Muhammad, peace be upon him; Isa, peace be upon him), then it is permissible to wear them, but it is disliked to enter the bathroom with them, in order to protect the names of Allah and the prophets from disrespect.