Salaah

Q: If someone forgets to pray Zuhr Salaah and he now prays Asr Salaah before he remembers that he had not prayed Zuhr Salaah, what should he do?

Q: In the Jalsa or Ruku in prayer, we have to stop for at least one Subhanallah, but do we have to sit in Jalsa completely motionless, or is it okay if we sit for at least one Subhanallah but in that time our arm moved a little or our leg(s) moved a little? The same question is for Ruku too, do we have to be completely motionless, or is it okay that we be in Ruku for at least one Subhanallah but during that time we move a little? 

Q: In Asr prayer in Jamaat, when we stood up for the second Rakat, I said Bi, I had to say Bismillahirrahmanirrahim, but then I remembered that in Jamaat, we don't have to recite behind Imam, the Qira'at of Imam is enough for us, so I stopped after just saying Bi. Was my prayer broken or is it valid? 

Q: I offer namaz alhamdulilah but I live in a shared flat with my cousin and he sleeps all day and works night shift and doesn't offer namaz. He is 10 years older than me. I have told him a few times to offer namaz but he doesn't. Will I get azaab (punishment) as well?

Q: If in the 2nd rakaat, you stand up and quickly within seconds realize you forgot to read tasahahud and you didn't start qirat yet, can you sit down and read tashahud then stand up again?

Q: Is it sunnah to place the right hand on the forehead after fardh salaah? If it is, what dua or zikr should be read while doing it?

Q: In a small Masjid, the Imam used a sutrah while leading the jamaat (it is a common practice in some places to do second or third jamaat if the main jamaat is missed). Is it permissible to pass in front of people who missed their rakaat with the Imam in these second/third jamaat are completing their prayers. Will they still be considered to be behind sutrah even if Imam has completed his own Prayer?

Q: As we know it is waajib to recite the first 3 verses of Surah Faatiha in every rakaah of salaah.

I heard a mufti say that qiraat changes the amount of verses in the Quraan. If I recite the first three verses of Surah Faatiha and combine the second and third verse and not recite further would my prayer be valid?

Q: I am reading my salaah alone and I am not sure whether I read 1 rakaat or 2 rakaats. Should I make sajida sahw or break the salaah and restart again.

Q: What's the sunnah method of reading Surah Faatiha in salaah? Each ayah a different breath? Or joining more than one ayah in one breath?