Entanglement Limitations vs Possibilities?

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I read this article on quantum entangled pairs in an ultra-cold gas:

http://www.trnmag.com/Stories/2005/050405/Noisy_snapshots_show_quantum_weirdness_Brief_050405.html

Hmm, scanning constellations of atoms within gas clouds, just as you'd
scan for constellations of stars in the sky. ;)

So can someone explain to me once again why quantum entanglement can't
be used for some kind of Faster-Than-Light communication again? I know
everyone says that would violated laws of physics, but I just want to
understand why again.

I know some say that entanglement isn't supposed to be possible over
vast astronomical distances, but what is actually limiting this
entanglement distance?

Nextly, is it absolutely true that it's absolutely impossible to probe
entangled states without destroying the entanglement? Is this just an
observation, or is there some inherent underlying reason why this can't
be done? From what I've read, researchers are learning how to
momentarily perturb an entangled state to read it, as opposed to
permanently destroying that state. If an entangled state is only
briefly and slightly perturbed by scanning and then returns to the way
it was before the scanning, then won't the entanglement remain?

I would note that researchers are now finding ways to image electronic
orbitals of atoms using photons, so that the disruptive effect of the
imaging is minimized.

Is there any inherent difference in the maximum allowable entanglement
distance for different types of entangled pairs? For instance, would
entangled atoms have a lower distance range to remain entangled as
compared to entangled photons or entangled electrons?

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