Various masaail of Jamaat Salaah and Imaamat

Q: What is the correct way to pray the Salats of Zuhr and Asr behind the Imam? Also, please, explain what is the correct way to perform the third Rak'ah of Maghrib and third and fourth Rak'ah of Isha behind the imam. Should a Muqtadi (person praying Jamaat behind Imam) recite Fatiha and Surah in the first two Rak'ahs of Asr and Zuhr and then recite Fatiha only in the last two Rak'ahs of Zuhr and Asr? Also should the Muqtadi recite Fatiha in the third Rak'ah of Maghrib and in third and fourth Rak'ah of Isha or should he stay quite? You I have to read inni and sana before surah fatiha in jamaat and in sunnat prayers shall I recite inni and sana? While performing prayer alone of maghrib what to recite in the third rakat?

Q:

1. If an imam has no duties except leading farad prayer, is his salary a price/ reward for his salaah? Is it not worshipping for money? Is it halaal to charge for what has been obligated by Allah Ta'ala?

2. If you employ a Hafiz to lead taraweh prayer in Ramadan, is his worship (for money) permissible and is the worship of his followers, behind him, acceptable before Allah Ta'ala?

3. When children are taught Quran by a paid tutor, is the teacher allowed to accept this material reward and still be 'khyrokum munn ta allaml quraana wa allama hoo'?

4. If it is not permissible to trade your (farad or sunnah) Ibadat for money/ receive salary, how should Imams of masjids and tutors run their household and kitchen?

Please advise in full detail with references from Quran and Sunnah.

Q: If a person performing Salaah behind an Imaan happens to repeat the Takbeer with the Imaam, is the Salaah valid?

Q: When a person joins the Salaat with Jamaat behind the Imaam and the person omits the three times Tasbeehaat in the ruku or sajdah, is the Salaah valid or does it have to be repeated?

Q: What is the status of a musalli's Salaah that precedes the Imam e.g. makes sujood before the Imaam?

Q: When your praying namaz behind the Imam, in every salah in the final rakat when you are seated in tashahhud, the minimum you have to recite is the tashahhud dua and if you start reciting durood and the Imam does salam then you have to do salam as well whether you have finished reciting the durood and dua or not, is this true? And in Zuhr, Asar, Maghrib and Esha, after the second rakat when you are seated in tashahhud and you are reciting the tashahhud dua, if you havn't finished reciting the dua and the Imam stands up for the 3rd rakat, do you finish reciting the dua and then stand up or do you follow the Imam and stand up even if you haven't finished reciting the tashahhud dua?

Q: Because of the Musjid being overcrowded and the mimbar being an obstruction in the first saff of the Musjid, a muqtadi happened to stand in the first saff directly in front of the mimbar, and when he (muqtadi) went into sajdah, his head touched the first step of the mimbar (he basically made the sajdahs with his head touching the first step of the mimbar). In the above mentioned case, was his (muqtadi's) salaah valid since he carried out his sajdahs in this manner?

Q: I am at home and the zuhr prayer jamat will soon start in the masjid and I have only a few minutes to perform my 4 sunnats. If I perform the sunnats before I leave for the masjid, I will miss the beginning of the jamat (I will catch the last 1-2 rakats). Should I do this, or should I instead leave early to the masjid and pray the 4 sunnats after the fard, thus catching the jamaat from its beginning?

Q: When performing Salaah behind an Imaam, what should one recite in the standing posture? Will one have to recite Surah Faatiha and a Surah?

Q: I have lead a congregation with no wudu intentionally. I cannot inform the people because it was on a holiday when I was overseas. What must I do? Will Allah forgive me?