Is it permissible, forbidden, or doubtful to work as a cook by arranging with other female cooks to prepare orders for customers without their knowledge of leaving the country, and bearing the responsibility of customer satisfaction in case of a problem?

It is permissible for the hirer to hire another person to perform the agreed-upon work, unless the first hirer stipulated that the hired person must perform the work himself, or if the work is such that it varies with different individuals, and no one other than the hired person can substitute for him due to a distinguishing quality. This applies to both the rental contract (ijarah) and the manufacturing contract (istisna'). If the customer did not stipulate that you must do the cooking yourself, and did not intend to hire you specifically for your individual person, then there is no harm in agreeing with another female cook to perform the work for a lower wage, with you taking the difference, while observing the requirement to specify the type, kind, quantity, and characteristics of the manufactured item in the istisna' contract.