Here's an alternative theory. It fits in with your theory of veils and other worlds. I hope it helps.
Recently I was watching the end part of an episode of Ancient Aliens: The Series. An episode called "Angels and Aliens."
In the episode the talked about a new term called Ultra-Terrestrial. Meaning something from another dimention or higher
plane of existance. Some examples given were ghosts and fairies
. According to the episode an Ultraterrestrial has
the ability to cross between worlds because they vibrate at a high frequency than humans do. I think they mean the atoms
that make up all things. So that could help explain things.
While writing this I Googled Ultraterrestrials and found something more in line your theory Aethra. http://www.conspiracyarchive.com/UFOs/ufofairies.htm
Also in Wiccan belief there is a time of the year where it is believed that the "veil" between this life and the afterlife is thinnest.
This interestingly occurs around what we call Halloween. If I'm getting my facts right it's called Samhaim and pronounced Sau-win.
It is my hope that something out of what I said is helpful.
Aethra wrote:I never really considered aliens until long after I considered the possibility of human evolution as a
result of return to the water. The whole reason I became interested in aliens is because if you take the aquatic ape theory
one step further you basically get what we know as aliens, specifically 'greys'.
I read a theory somewhere that "Greys," sometimes refered to as Zeta Reticulans evolved from a Cetacean like lifeform.
They come to Earth for whatever reasons, but are from another world.
While reading your post it reminded me of Battlestar Galactica.