Demolishing the Masjid his father built years ago and rebuilding it to provide an income for it

Q: First, our father (may Allah be merciful to him) built a Masjid (mosque) a long time before his death. He asked his children to maintain, repair and do all the required tasks for the Masjid. He also asked them to prepare the Masjid for performing the five daily Salahs (Prayer). We decided, due to the antiquity of the Masjid and the large number of people who currently pray there, to pull it down in order to expand and rebuild it according to a modern style. (Part No. 16; Page No. 340) We decided that in order to increase the area of this Masjid, to build a basement that contains shops in the opposite direction to the main road. On the other side, we will build a residence for the Imam and the Mu'adhin (caller to Prayer) and the minaret. In the northern area, we will build places for making Wudu' (ablution) and a water tank. The Masjid will be above the ground floor meaning above these shops and residences. The area will be vast because there will be balconies in three directions. The Masjid will be away from the noise of the surrounding streets. Ascension to the Masjid will be very easy because of comfortable and small steps. There will be no more than ten steps due to the lowness of the Masjid floor. Doing so will bring about two benefits:First, adding more area to the actual seize of the Masjid can be achieved through using the roofs of these shops as they are equal in height to the floor of the Masjid, and also by adding to the Masjid the areas of the balconies.Second, having constant and permanent revenue that can be used for maintaining and repairing the Masjid in the future. This revenue will also help with providing the Masjid with an Imam, a Mu'adhin (caller to Prayer) and a guard and everything that is required for the benefit of the Masjid. This revenue will guarantee taking care of the Masjid generation after generation without neglecting it. (Part No. 16; Page No. 341) All these things will be for the Sake of Allah (Exalted be He) whom we ask to provide us with more support and success.We would like Your Eminence and the members of your honorable Committee to give us a Fatwa concerning building such a Masjid according to the aforementioned method.