Kufr

Q: Can we make takfeer of all the Shia?

Q: We all know that qadayanis are not Muslim as they do not believe in khatm-e-naboowat sallallahu alaihi wasallam. If a qadaayani becomes hafiz of the Quraan, what would happen to him/her in this case as he is not a Muslim?

Q: I recently discovered that some of my past actions were kufr and I sent some messages containing shirk. I have sincerely repented and vowed never to do them again. I made a general taubah regarding all my past actions then recited kalimah.

1. I would like to ask if it is necessary to repent specifically for each action as all I have thought about since is remembering specific kalimat I said. Do I need to do tajdeed e iman again if I remember those past actions after making general taubah?

2. Also do I need to perform ghusl after tajdeed e iman?

3. Can tajdeed e iman be made whenn one is junub.

4. What about my prayers that I said while not realising my kufr?

Q: I suffer from doubts regarding many things. I am constantly remembering jokes and statements I made in the past that may have been statements of kufr. I have recently read about people singing certain songs that may have taken them out of the fold of Islam. Alhamdulillah I do not listen to music anymore. However I remember listening to and singing the same songs many years ago. I did not know the meaning of these songs at the time. I am now doubting the validity of my nikah and legitimacy of my children due to my actions prior to and after nikah. Is my nikah valid if I have commited these actions prior to nikah?