Fajr Sunnah, Joining the Congregation, and Catching a Rak'ah

Read-only question overview. Answers and scoring remain inside authenticated learner attempts.

• The Fajr Fard congregation has begun. When may a person perform the 2 Fajr Sunnah rak'ahs first?
• For this Fajr-Sunnah exception, the commentary even records catching the final sitting as enough to avoid complete loss of the congregation.
• Where should the Fajr Sunnah be performed if the Fard congregation has already begun?
• The primary matn rule says the missed Fajr Sunnah is always made up by itself immediately after the Fard.
• If both the Fajr Sunnah and Fard were missed together, when does the source allow making them up?
• A follower catches a rak'ah merely by saying the opening Takbir while the prayer leader is in Ruku, even if the follower never reaches Ruku before the leader rises.
• Match the situation with the ruling.
• A person already prayed Isha alone and, before leaving, an Isha congregation is established. What does the source allow?
• According to the preferred ordering stated here, when are the 4 missed pre-Zuhr Sunnah rak'ahs performed?