Is marriage to a woman who has performed khulʿ valid in Islamic law if it occurred without her observing the waiting period, and how can this be rectified given the doubt about the wife's pregnancy, and what is the waiting period for a woman who performed khulʿ but separated from her husband a year before the khulʿ?

The woman who seeks khul' (divorce at the wife's instance) is obligated to observe the 'iddah (waiting period) by the consensus of scholars. It is incumbent upon the man who marries her during her 'iddah to separate from her. She must first complete the 'iddah of khul', and then observe the 'iddah from him. If the wife is pregnant by the second husband, the child is attributed to him, and the husband must separate from her until she delivers her child and her 'iddah ends. He can then remarry her if he wishes.