Saying 'Alhamdulillah' doesn't have any effect in the finality of the ghusl, so you can continue it and complete it after that if there is a part that you have missed. However, you can consider the ghusl to be complete and valid if the doubt arose after finishing the ghusl.
She should make up the purposefully missed fasts, in addition to paying the kaffara for each day missed on purpose. She also should make up for the days that she missed when she was sick before the next Ramadan. If she did not make up for them before the next Ramadan when she could have done so then she should make up for those days as well as pay the fidya for each day. An amount of 900 grams of dates, wheat, floor, rice, lentils and the like for every missed fast must be given to the needy people as fidya for each day. If she could not make up the missed fasts, she should put in her will that someone should make up for the missed fasts after her death.
No, it is not recommended to do so.
Smoking tobacco whether it was in Shisha or cigarette is permissible.