sajda-e-sahw

Namaaz me ghalati karna

Q:

1. Agar koi shakhs Imaam saheb ke salaam pherne ke baad bhi kuch dair tak salaam na phere apni namaaz jaari rakhe, yani Imaam saheb salaam phair ke muqtadiyo ki tarf munh phair ke beth jaye aur wo shakhs apna darood sharif and dua puri kar ke salaam phaire uske baare me kya hukam he?

2. Witar ki musalsal teen rakaat parh rahe hon aur doosry rakaat ke baad tashahud ke baad bhool kar darood shareef bhi parrh liya jaye to kya sajda-e-sahw karna ho ga ya namaaz saheeh hogi.

Sajda-e-sahw

Q: Can you please explain uptil when sajda-e-sahw can be done for unintentionally missing out a wajib in the prayer? If a person unintentionally leaves out a wajib, and they have done salaam, can they still do sajda-e-sahw? Also, if a person does not do sajda-e-sahw, and the prayer time has ended, will they have to redo the prayer? I have heard that the prayer will have to be redone for leaving out a sajda-e-sahw as long as its still the prayer time, but after the prayer time has passed, it is not mandatory to redo the prayer, but recommended to. Please if you can explain.

Forgetting to recite a Surah in the third rakaat of Sunnat Salaah

Q: I performed the four sunnah of Asr salaah however in the 3rd rakaat I forgot to read a Surah after Surah Fatiha only realised this in ruku. I intended to make sajda sahwa but after the 4th rakaat I read the tashahud, durood and dua and made both salaams. Whilst making the second salaam I remembered the sajda-e-sahw and immediately made a sajda after then completed the Salaah. Was I correct or did I have to repeat the Salaah?