Is a girl who has religiously agreed to marry considered a fiancée, despite her family not being officially informed, and her father being deceased with a brother alive?

The original principle is for the marriage proposal (khitba) to be made through the woman's guardians. However, it is permissible to propose directly to a mature woman herself, provided there is no fear of fitna (strife/temptation). If the girl is mature, then the proposal has been made as mentioned. However, a proposal is merely a promise of marriage, and nothing of the woman becomes permissible to the suitor except the lawful gaze. The suitor remains a stranger to the woman he has proposed to, and he is not permitted to exchange words of love and flirtation with her, or to expand in conversation or correspondence.