1- A Muslim is obliged to believe in every idea for which there is evidence in the Quran or the Sunnah. 2- The basic principle is to accept the absolute power of Allah. 3- Allah created Adam and he was sixty cubits tall. For more, please see the detailed answer.

When a person dies, he moves from this world to another realm, and his soul does not come back to his family and they do not feel anything of him. The dead person does not know anything about the circumstances of his family, but Allah may inform some of the dead of some of the circumstances of their families, but this is not necessarily so.