1. Golden Ankh. The objects Goblet, Idol, Zebra, Ankh spell out GIZA, the Egyptian city where the pyramids are.
2. California. The words "Lair of Cain" in the title are an anagram for "California".
3. The letter "P". The series is the nine planets of the solar system: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, Pluto.
4. The five digit password is GREEN. The children's names were ROY and BIV. The seven colours of the rainbow are red, orange, yellow, green, blue, indigo, violet. The first letters of these colours are ROYGBIV. The only letter not used in one of the children's names is G, which stands for Green.