1) When can I ignore the doubt about having done qiyam before ruku

2) In jamaat, In 1st rakaat after coming back from sajdah I see the Imam beginning to do bihaw lilah is my jamaat in order ?

3) When making a mistake that needs sajdah sahv – example I talked by mistake do I need to do 2 sajdah sahv per mistake or one sajdah
-As in 2 regular sujood = 1 sajdah sahv or 4 regular

4) How do I treat doubt about having recited tasbihate arba 3 times already both in furada and jamaat

5) How do I treat doubt after salah time has passed about having prayed earlier or later

1- Once you are in Rukoo

2- The question is not clear. Do you mean that he starts standing up after the first Sajdah?If it is the case, then you need to do the second sojood, not to follow him.

3- For each mistake you need separate sojood Sahw
4- Do not pay attention to all this. One time tasbehht is enough.