Is what the questioner did, by helping his wife's sister leave Iraq and divorce her husband, who does not fulfill his religious obligations, and her refusal to return to him after he showed leniency, a correct action or not? And what are the consequences for him and his household?

The action you took—which is taking the woman out of Iraq, separating her from her two children and her husband, and her traveling for Hajj without a mahram (definition) and without her husband's permission—is incorrect, and you incur sin for it. You must repent and seek forgiveness. A wife's departure from her home is not permissible except with her husband's permission, and similarly, it is not permissible for a woman to travel without a mahram. If she suffers harm from her husband, she should refer her case to the judge.