Is it permissible for a woman to pray the regular Sunnah prayers that precede a fard prayer, such as the regular Sunnah prayer before Dhuhr, after the iqamah has been called, given that congregational prayer is not obligatory for her?

If the prayer is established, then there is no prayer except the obligatory one. This ruling applies to whoever is addressed by the congregational prayer or is present in the mosque at the time of the call to prayer (Iqamah). As for a woman in her home, and a man excused from attending the congregational prayer, it is permissible for them to perform supererogatory prayers while hearing the Iqamah. The same applies to a man if he intends to pray in another mosque different from the one where the prayer has been established. The generality of the Hadith includes the prohibition of commencing any supererogatory prayer, whether absolute or regular, in the mosque or elsewhere, even at home, if the prayer which the Muslim intends to pray with its Imam has been established.