Answered by Shaykh Yusuf Weltch
Under what conditions can a marriage contract be done without a wali or witnesses?
Under what circumstances can a marriage contract happen without a wali or witnesses?
In the Name of Allah, the Most Merciful and Compassionate
Though not permitted, except under circumstances of religiously recognized necessity, marriage is valid without the consent of a guardian; however, marriage is not valid without at least two adult Muslim witnesses, either two males or one male and two females. [Maydani, al-Lubab fi Sharh al-Kitab]
If one’s guardian refuses to consent to marriage without valid reason or excuse and this results in undue harm or hardship on the woman, an Islamic jurist (mufti) may appoint her an agent (wakil) to act as the consenting party. Another example of this would be if the woman’s guardians are all non-muslims.
However, this is no light matter. Even though consent is not a condition of validity of the marriage the guardian has the right of annulment of the marriage, if, without consent, she marries someone who is not seen as Islamically compatible with her. Compatibility is stipulated by specific criteria set by the Sacred law. [Ibid.]
Hope this helps
Allah knows best
[Shaykh] Yusuf Weltch
Checked and Approved by Shaykh Faraz Rabbani