What are the regulations and conditions for a bride wearing a white wedding dress in front of women, and is it permissible for her to leave her parents' home in it to go to her husband's home, or must she wear an abaya and niqab to conceal her adornment from non-mahram men? And what is the evidence for that?

If the white wedding dress is to be worn only in front of women, then it is a condition that it covers the 'awrah (what is between the navel and the knee according to the majority of scholars), and it is preferable to cover what is usually exposed, while avoiding extravagance.

As for the bride appearing in it before non-mahram men, it is not permissible unless the dress covers the entire body and fulfills the conditions of the Sharia-compliant hijab; otherwise, she must wear something that covers it.

Regarding covering the face, the bride is required to cover her face due to the adornment on it, even though the obligation of covering it is a matter of scholarly disagreement.