During engagement ceremonies, it is important to follow the boundaries set by Shariah. If the Nikkah has not yet been conducted at the time of the engagement, the engagement itself is only a promise to get married.
Therefore, the fiancées are still considered non-mahrams to each other. Consequently, sitting together and conducting rituals in this manner is considered sinful. It is therefore necessary to refrain from such practices.
Allah the Almighty knows best.
Darul ifta Al-Ikhlas, Karachi.