All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and messenger.
A valid marriage contract as per the Islamic Sharee'ah requires an offer or proposal of marriage (Eejaab) and an expression of acceptance of the proposal (Qabool) and should be conducted in the presence of the bride’s Wali (matrimonial guardian) and (two) witnesses. Please refer to Fatwa 83629.
Hence, if the matter was nothing but organizing a wedding ceremony, this is not considered a valid marriage as per the Sharee'ah. It does not have any legal effect or implications and this woman is legally and Islamically unmarried and is allowed to marry any other man.
However, if there was a proposal of marriage (Eejaab) and an expression of acceptance (Qabool) and there were witnesses to such a marriage, but the bride’s Wali was not present, then the marriage is considered defective (lacks one or some of the requirements of a valid marriage as per Sharee'ah), and it should be annulled. As long as the marriage has not been consummated, there is no ‘Iddah (post-divorce waiting period) for the woman. She is entitled to marry this man or any other man according to the Islamic Sharee'ah (right after the marriage annulment).
It is worth noting that the marriage contract should not necessarily be carried out by a Shaykh. Also, the fact that the Mahr was not specified in the marriage contract does not affect its validity since the Mahr is not a requirement for the validity of the marriage contract or one of its pillars. This is the view of the majority of Muslim scholars. It is considered one of the implications of the marriage contract, but if the marriage contract is conducted without specifying a Mahr, it is valid according to scholarly consensus.
It should be underlined that if a husband divorces his wife and then holds the intention to revoke the divorce and take her back in marriage without declaring or uttering that (to others), the revocation of divorce is invalid by the husband’s intention only (without clearly expressing his will to take her back in marriage). Please, refer to Fatwa 91136.
If divorce takes place before consummating the marriage, there is no ‘Iddah for the woman as highlighted above.
Allaah Knows best.