Is what transpired between the suitor and his fiancée considered a valid marriage contract, and is the dissolution of the engagement considered a divorce, with its resultant implications regarding the dowry?

If the husband appoints his father as his representative for the marriage contract, it is valid. Even if he does not appoint him, the contract is also valid according to the majority of scholars, based on the husband's approval, even if the acceptance precedes the offer. This marriage is not considered an engagement and its validity is not nullified by not being documented. Regarding the annulment of the marriage, if the husband says, "I annulled the engagement or the marriage," and he does not intend divorce, then there is no consequence for him. However, if he intends divorce or utters an explicit divorce pronouncement, it is effective. In the case of divorce before consummation or seclusion, it is an irrevocable divorce, and the wife is entitled to half of the mahr. The guardian must return the other half if he had taken it. However, if consummation or seclusion has occurred, the wife is entitled to the full mahr, and the husband can take her back before the 'iddah (definition) is complete. Divorce takes effect immediately upon the husband's pronouncement and does not require witnesses.