Is it permissible to place the minbar and the mihrab on the second floor of the mosque, while there are worshippers on the first floor, and is it permissible for the imam to be above the worshippers?

It is more complete for the Imam and the congregants to be at the same level. The majority of scholars have stipulated that it is disliked for the Imam to be higher than the congregants, though not vice-versa, because the imamate is a position prone to arrogance. The Shafi'is consider it disliked for either to be elevated above the other, except out of necessity, such as teaching the congregants. The narrowness of the ground floor is a sufficient excuse, and it is preferable for the Imam to be on the ground floor, with those who cannot find a place praying on the upper floor.