Iron-56 and atom with 27 protons and 29 neutrons.... Are the atoms isotopes of the same element? Why?

No because iron's atomic number is 26, which is the amount of protons that atom has. For two atoms to be isotopes, they must be the same element (which means it has the same amount of protons) but a different number of neutrons. Both these atoms may have the same m, but since they have a different number of protons, they are not isotopes.