Is it permissible for men to wear silver bracelets and necklaces?

All Praise is due Allah, The Lord of The Worlds

Men are allowed to wear silver rings, but they aren`t allowed to wear bracelets and necklaces because by doing so they imitate women. And Allah Knows Best.

What is the expiation for perjury?

One who commits perjury should repent, seek Allah`s forgiveness and offer an expiation which is: feeding ten indigent persons, or clothing them, or giving a slave his freedom, but if that is beyond his means then, he should fast for three days. Allah, The Almighty, Says in this regard (What means): "Allah will not call you to account for what is futile in your oaths, but He will call you to account for your deliberate oaths: for expiation, feed ten indigent persons, on a scale of the average for the food of your families; or clothe them; or give a slave his freedom. If that is beyond your means, fast for three days. That is the expiation for the oaths ye have sworn. But keep to your oaths. Thus doth Allah make clear to you His signs, that ye may be grateful." [Al-Ma`idah/89].

How long is the` Iddah (waiting period) of a divorced woman?

The waiting period (iddah) of a divorced woman who is pregnant is until she gives birth. If she is of menstruating age, her waiting period is three menstrual cycles. If she does not menstruate, her waiting period is three months. And Allah Knows Best.

Is it permissible for a young man and a young woman to enter into a covenant as a married couple without having a true seclusion (Khalwah) until their marriage contract is officially concluded?

The relation which isn`t based on a marriage contract is forbidden, and entering into a covenant as a married couple is unaccounted for and is from the evil suggestions of the devil.