It is better to limit it to saying Bismillah when starting to eat, and not add anything to it. But if one does add to it by saying Bismillah Ar-Rahman Ar-Rahim, there is nothing wrong with that according to the majority of scholars.

It is not permissible for anyone to attend the wedding feast except with the permission of the host. An exception to that is made if, according to the custom of the people and the host of the wedding feast, he would be happy for a person to eat at the wedding feast even if he attends without an invitation. Implicit permission is the same as explicit permission.

There is nothing wrong with a woman who is Junub cooking, looking after her house, taking care of her children or fulfilling any other needs.

Extravagance leads to overstepping the mark, which means eating beyond the point of fullness. This is not limited to one or two or three meals a day. A person may eat one meal a day and eat extravagantly during that meal. Or he may eat three meals without being extravagant.