To (hopefully) answer this all at once, science's limit in this case would be the human ability to see the links, but the links still trace clearly back to some sort of entity that has (at least in part) a material existence.
God as a "spiritual concept" would have no method to interact with...
I...don't...know? I'm wary about claiming to know what corresponds to reality in general, since we only have perceptions of reality to go off of.
So probably nay here.
Both of these would require a god-concept with no interaction with the physical/material/energetic world.
As for the Hamlet thing, some literary critic has probably already done it. :p
Only if your current spiritual model agrees with the scientific model. What's to say they won't conflict? Or is your spiritual model merely derivative of scientific discovery?
If you know that beating your wife causes activation of her pain receptors and wounds her psychologically as well as physically, would you follow another "assumption" that says beating her is morally acceptable?
Might have been in the chat. Anywho, it sounds plausible. Being able to create a mental model of self helps to coordinate the body, which would allow for better defense. I doubt it's the only reason (or main reason) but it seems to be one of many perks to its development.