Avatar or Expansion of Krishna: Lord Nrsimhadeva

Q. After we worship Lord Krishna, why do we only glorify Lord Narasimhadeva and no one else like Lord Rama, Vishnu, Venkateshwara etc.?

Q. It is stated that all the Vishnu forms are eternal. Are there separate lokas for the Kurma, Matsya, Varaha, Narasimha, Rishabhadev, Parasurama forms? If so why does the Bhagavatam say that the form of Narasimha was never seen by anybody before? And also what about the form of Lord Caitanya? If He is eternal, where is His planet?

Q. In Hindu culture, in all pujas we used to pray first for Ganesa but we are not following this. Why?

Q. Avatar means to descend. That means all avatars exist in various Vaikunta lokhas. Do all avatars exist in the form in which they descend. For example does Lord Narasimhadev exist in the form in which we worship him, or He exists as a four armed Vishnu form. If Vishnu form then why is it that Lord Krishna and Rama are in the same form in which they descend?