Masbooq and Laahiq

Q: What is the last moment within which if a person joins the Imam in congregation Salah then he will get the congregation?

Q: In a maghrib salaah, if I join the jamaat in the third rakat, the next two rakats do I have to recite a surah after surah fatiha? Do I have to sit in tashahud in both the remaining rakats? Similarly, how do I do it in isha if I joined in the last rakat?

Q: Please help answer this based on the Shafi'ee mazhab. If a musalli joins the congregrational prayer and he joins when the Imam is in ruku, will he still get one rakaat, how about al fatihah that he did not read for this rakaat?

Q: When I came late for salaah and had to complete missed rakaats I read durood-e-ibrahim and dua. Does this make sajdah sawhu waajib? If yes and previously I should do this out of ignorance and cannot not remember how many times are done it what should I do?

Q: A masbooq makes both salaams with the Imaam and then realizes that he is a masbooq. How should he complete his salaah?

Q: Is there any Hadith about joining the masbooq in Jamat?

Q: A masbooq missed one rakaat with the Imaam. When the Imam sat in Qa'ada Akheera the masbooq recited the durood and dua. Should he make sajda sahwu after he completes his missed rakaat?

Q: If I am a masbooq and I mistakenly make one salaam with the Imam. Then I realise my mistake and stand up to complete my missed rakats, should I make Sajda Sahw?