I have further questions, I will number them to make it easier to read:
1. Okay, so a naga is essentially a self-realized human being that exists within the waters of heaven, would that be Eden?
2. What is the difference between a self-realized human being, an angel or a god?
3. In Buddhism we hear of the humans, Demigods and Gods, where do the angels and self-realized humans fit into their system?
4. If nagas and angels are the same thing, why are they depicted differently in each tradition?
1. Yes. But remember: Eden is a state of consciousness. The waters are not physical, literal.
2. They are all the same thing.
3. In the context of Buddhism, these three terms refer to beings who have their consciousness at their corresponding level; they are still on the wheel of becoming, have ego relative to their level, and are chained by karma at their level. Really, it is just a matter of conditioning, since all of us have experienced all of these states. From the widest point of view, there is no fundamental difference between them, since they remain enslaved by the wheel of becoming.
4. The word naga can be used in many ways. Anyone with Kundalini awakened becomes a "naga" at their level. So in this sense, the word is very broad.
More specifically, there is also a race of Nagas. These are a particular race of human beings who did not leave Eden. They did not fall. They have their own civilization, culture, powers, etc. but this humanity lacks the ability to perceive them. On occasion, they make appearances in "our" world in order to help us, but they do so secretly.
Every tradition reflects a different psychology. What Christians call Angels, the Greeks called gods, Titans, etc. Each populace has differing needs, so their traditions developed in relation to their way of thinking. Stated another way, each master gives the same knowledge, but the students who receive it interpret it at their level and by their unique culture. Over time, as students propagate their traditions, differences emerge and become pronounced. In the core, the beginning, it is the same teaching. So, traditionally, the serpent (Naga) has a very different psychological flavor in India, as compared with Judeo-Christian-Muslim traditions. Jews, Christians or Muslims simply would not accept that their angels are "serpents, nagas" even though they are, since they have the "serpents" arisen in the spinal columns. In their case, that force is called the fire of the pentacost. It is the same energy.