Straightening the saffs

Q: If I am in the first row for Salaah, and there is an aalim in the second row, can I offer him my place in the first row?

Q: In fard salaah, if a persons wudhu breaks infront of you, can the person behind him take his place by moving forward? What is the best option in this regard?

Q:

1. How many saffs (rows) can we cross while in the state of namaaz in order to fill the front saffs (rows)?

2. How much can we move horizontally in the same saff (row) in order to fill the gap?

Q: Two people were performing salaah with jamaat. Thereafter, a second muqtadi joined the jamaat, but the first muqtadi did not move back to stand with him behind the Imaam. In this case, should the Imaam move forward?

Q: In a Masjid, a row is usually left empty after every few rows, as it has several pillars.

1. If it is left empty, is the Salah of those behind it valid?

2. Is Salah valid between the pillars?

3. Once, people prayed in that row to the right of a pillar, but to the left of the pillar the row was empty. Was the Salah of those who prayed to the right of the pillar valid?

Q: If one prays in congregation, but due to people praying ahead, he cannot join the saffs ahead, is it permissible:

1. To pray behind an empty space between him and the safs ahead where more than two safs can be formed?

2. OR should he pass in front of musalles to go ahead? What about in the Haram Shareef in Makkah Mukarramah and Masjid Nabwi? Are we allowed to pass in front of musalles?

3. If one prayed behind with an empty space ahead, does the salah need to be repeated?

4. If needs to be repeated, if the prayed salah was janazah, what intention to make for the repeated salah, nafl as janazah salah perhaps cannot be repeated?

Q: Some masaajid have a two-storey building. Is the reward for praying in the first row of the second floor equal to that of praying in the first row of the first floor?

Q: If a person comes last in the masjid and there is no space in the first row

1. Should he slightly pull a person from the first row to stand next to him?

2. If the person from the first row comes back to join the person standing alone in the back, what should be the duty of the men who were standing left and right of the person who went back? Should they remain in their places or move closer? What is the proper way to fill that space? 

Q: I was leading the Asr prayer and there was only one young boy along with me who stood on my left instead of my right. Is this Jama'ah correct, or should I repeat this prayer?

Q: When two people pray together, should the follower stand next to and parallel to the imam, or should he stand slightly behind? I have heard conflicting opinions regarding this.