Does the engagement (Khutubah) fulfill the purpose of the legal marriage contract (Aqd Shar'i) and is it considered to have the same حكم (ruling), especially if this is the prevailing custom in the country, as is the case in Tunisia, and did the Maliki school of thought state this?

The engagement does not take the place of the legal contract, and marriage is not legally concluded except through offer and acceptance between the woman's guardian or his proxy and the husband or his proxy, in the presence of two witnesses. It is not a condition for the validity of the contract that it be documented in courts. The engagement is merely a promise of marriage and a prelude to the legal contract; it is not binding and does not constitute marriage.