Is the bride's dress considered a bid'ah (innovation in religion) and a thwab shuhrah (garment of vanity), and what are the objectionable practices in weddings?

A distinction must be made between Bid'ah (innovation in religion) and forbidden acts (Muharramat). Bid'ah is an invented method in religion for drawing closer to Allah. As for forbidden acts (such as adultery and drinking alcohol), they are not called innovations. A wedding dress is not an innovation because it is not a method in religion nor is it intended as a means of drawing closer to Allah. The general rule for clothing is permissibility, unless it includes something forbidden. A wedding dress might include certain prohibitions, such as imitating the enemies of Allah, extravagance and wastefulness, and immodesty. If the dress is free from these prohibitions and the woman does not appear in it before non-mahram men, then it is apparently permissible.