"Its hard for me to make a connection between the words of a 19th century yogi and Mesopotamian palace facade architecture found at the beginning of Dynastic Egypt."
Briefly, Ramakrishna was said to be an incarnation of Rama and also Krishna. Rama's historical context is approx. 5000 BC and Krishna's is approx. 3000 BC. So the timeframes coincide with Sumeria and early Egypt. The spiritual thoughts of the Aryans have remained largely unchanged throughout history down to the present day and the form of yoga which Ramakrishna practised, dates back to the earliest recorded times.
It is quite likely that the Sumerians and also the Ancient Egyptians, amongst others, were also Aryans, and had their ethnicity diluted over time. Although modern Hindus, who have embraced the old religion, cremate their dead, this is a more recent custom. The preservation of the body was extremely important to later Dynastic Egyptians, but may not have been the case in pre Dynastic times - hence the lack of bodies in tombs.
Those familiar with the practice of meditation will understand the significance of the seven gates. The symbolism of the serpent is most appropriate and still has much significance in current yoga. Upon death each pharaoh became Horus, ascended and became one with God, keeping in mind that "death" can occur before one actually dies, hence the concept of rebirth - the one known as Jesus being reborn after an encounter with The Baptiser and the process symbolized by a dove being a more familiar version.