Does a father's feeling of sadness that his fetus is female after he thought it was male, and his prayer for the fetus to be male, and his concealing his sadness from his wife, contradict having a good opinion of Allah?

There is no blame upon you for what has befallen you, as long as it is merely a feeling in the heart and not a sign of discontent with divine decree. It is not forbidden for you to inform your husband of your condition, for that is not a sign of impatience if it is accompanied by acceptance of Allah's decree. Indeed, the Prophet (peace be upon him) and Ayyub (Job) (peace be upon him) both complained. What comforts the believer is to remember that Allah may place much good in this, for a person may be blessed with a child who then disbelieves and causes distress to his parents, as came in the story of the boy whom Al-Khidr killed. You have already been blessed with a child before, and daughters have many virtues.