Q 3:
Do the Imam (the one who leads congregational Prayer) and Ma'mum (a person being led by an Imam in Prayer) have to offer Tahiyyat-ul-Masjid (two-unit Prayer to salute the mosque) if they offer the Sunnah (supererogatory) Salah of Fajr (dawn) Prayer at home then come to the Masjid to offer Fajr Prayer?
A:
If the situation is as you have mentioned, then they should perform Tahiyyat-ul-Masjid upon entering the Masjid (mosque) and before sitting. The Imam may initiate the Iqamah (call to start the Prayer) and hence he will not have to offer Tahiyyat-ul-Masjid because the obligatory Salah will be sufficient and the same ruling applies to the Ma'mum.May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.