Is the aforementioned marriage religiously valid, taking into account that the witnesses left before hearing the details of the contract, and did the Shaykh perform the guardianship correctly?

If a Muslim woman does not have a Muslim guardian, the Muslim judge or his representative can marry her, or she can appoint a trustworthy man. Testimony (of witnesses) is a condition for the validity of the contract, by agreement of the jurists. The majority of jurists state that witnesses must be present at the time of the contract. Therefore, the aforementioned contract is not valid, and subsequent announcement on Facebook holds no weight. The Maliki school of thought considers testimony desirable at the time of the contract and obligatory at the time of consummation. We advise repeating the marriage contract.