Is the aforementioned marriage contract Islamically valid, given the absence of one of the two witnesses and the guardian and husband not having verbally uttered the صيغتي الإيجاب والقبول (formulas of offer and acceptance)? And if it needs to be redone, must the entire contract be redone, or is it sufficient to merely utter the verbal formulas?

The majority of jurists hold that a marriage contract is only valid with verbal offer and acceptance. However, Shaykh al-Islam Ibn Taymiyyah and those who agreed with him differed, opining that marriage is valid by whatever people consider a marriage, in any language, wording, or action. The majority of jurists stipulate the presence of two just witnesses at the time of the contract, while the Malikis consider witnessing desirable at the time of the contract and obligatory at the time of consummation. Some jurists believe that the publicizing and widespread knowledge of the marriage suffice for witnessing, a view also mentioned by Ibn Taymiyyah. Therefore, if the matter of this marriage became widely known, it is considered valid, especially if consummation has occurred. Otherwise, it is preferable to re-perform the contract, ensuring all conditions are met.