Qadha and Kaffara

Q: Can one keep any qadha fasts as joint fasts with the six fasts of Shawaal or must one keep them separately?

Q: My wife missed Ramadhaan fasts due to menses. She also made niyyat to keep fast already due to the execution of some work.  My question is for which one she needs to give first priority (Whether it is Ramadhaan Fast or the other one?)

Q: Does a woman that missed fasts due to her having her periods have to pay Fidyah for the days she missed?

Q: If I keep the six fasts of Shawaal with the niyyat of qadha, will I receive the special reward of these six fasts? Also, is it correct for fasts besides Ramadaan fasts, niyyat has to be made before subah saadiq?

Q: The three fast for breaking a qasam have to be fasted together or with intervals?

Q: A relative of mine came from overseas for holiday. The wife carried hot water in a flask for the child's milk. At the airport in England, they asked her to drink the water (to see whether it is really water on something else). She explained that she is fasting. They said either she drinks little of the water or they will have to throw the water away. She therefore drank some of the water. Will she have to keep only qadhaa, or kaffarah as well?

Q: As a teenager I had a bad habit of masturbation, which I sincerely and deeply regret. The urge was very strong and I resorted to this sin even in the month of Ramadaan while in the state of Roza. I would keep the fast as usual, i.e have sehri, and abstain from food and drink until the time of iftaar, but on one occasion would commit this heinous sin. May Allah Ta'aala forgive me. Ameen.
This evil continued for approximately 8 - 10 yrs since I became baligh. Thereafter Allah Ta'aala assisted me to refrain from this sin. Alhumdulillah.
It is a source of constant worry for me, and I know that taubah is not enough to eradicate this evil deed. I know there is qadha as well as kaffarah that needs to be kept. I am however perplexed with how to go about this. My concerns are as follows:

Q: A man wished to donate a kidney to his son. He went to the hospital for a test and needed to drink a liquid to check if his kidney is compatible. Therefore, he broke his fast and drank the liquid. Does kaffarah become waajib on him or not?

Q: If a person whilst fasting masturbates will the fast break? If so will Qadha as well as Kaffarah become Waajib or only Qadha?

Q: After eating forgetfully, a fasting person intentionally ate, assuming that his fast had already broken. Does the fast now become nullified? If so, will qadha as well as kaffarah become waajib or only qadha?