So much to cover. 😁
What do you think about Ecclesiastes 9:5
I think you have to be careful when using OT passages in this context. Ancient Jewish views on the afterlife were that all people—good and bad alike—were believed to go to Sheol, a dark, silent pit where the dead lived on as weak shadows (shadaim or ghosts) without consciousness, praise of God, or active existence. So Jewish teaching at the time was that the dead knew nothing. That changes, along with many other things, in the NT.
Onto the consciousness issue and evidence from NDEs,
I am afraid they do not provide a scientific explanation for those events, only recount the evidence of them being reported. The article itself says:
The high percentage of accurate out-of-body observations during near-death experiences does not seem explainable by any possible physical brain function as it is currently known.
Correct, we do not have a scientific explanation for out-of-body experiences during NDE's, but we also do not have a scientific explanation for how consciousness arises in the first place. The standard scientific assumption is that it is a byproduct of brain activity. This is called the materialist explanation of consciousness. If there are large numbers of case reports in which people can reliably describe their observations of what happened to them while they were clinically dead and had no brain activity, the materialist explanation has a lot of explaining to do.
Another theory is called the transceiver model. In this model, the brain serves two functions. It acts as an interface to our physical bodies, and through them to the world around us, and it acts like a radio receiver or a filter, tuning in a universal or non-local stream of awareness into a single human focus. Think of it this way - if you turn off your TV set, does the program disappear? No, you just stopped receiving it. The signal is still out there.
There is a scientific theory as to how this could work, and it involves quantum physics.
https://aeon.co/essays/materialism-alone-cannot-explain-the-riddle-of-consciousness
We know that quantum physics is involved in many biological processes, like migratory bird navigation and photosynthesis, so why not consciousness?
https://en.wikipedia.org/wiki/Quantumbiology
On the question of reincarnation, I don't know what to believe. I don't think that children who remember past lives are being occupied by the souls of the deceased. I do think it's possible that as children, their brains are more open and that they have somehow connected to communication from the dead, including their memories. This goes back to the idea of the brain as a filter that normally blocks such communication. The filter theory may also explain acquired savant syndrome, in which people develop extraordinary abilities after having a brain injury.
https://www.psychologytoday.com/us/articles/202403/the-mystery-of-sudden-genius
The Episcopal Church takes no position on reincarnation.
I started looking into all of this because I have a scientific/technical education and mindset, and while I have faith in the afterlife, I like the satisfaction of understanding how things work, or at least a plausible theory as to how they work.