1) 8.42 says artillery disrupted as a result of assault combat stays in place rather than retreating, and that the guns are considered abandoned. Per the Errata/Q&A, a subsequent attacker advance after combat eliminates it. Such an advance after combat looks to be an exception to 8.521, which requires the hex to be completely clear of defenders before an advance can occur. Is it correct to conclude that, if the gunners have abandoned the guns, there is no defender, thus allowing the advance after combat?
2) If the guns are considered abandoned, is it correct to conclude that the Artillery cannot move until rallied (which, in this context, would seem to mean the crews returning to their guns)? Such a conclusion, however, would mean that the movement ratings on the backs of the artillery counters are meaningless.
3) Disrupted artillery has a combat value of zero, making it impossible to calculate odds when assaulting it. Is it therefore correct to conclude that, if alone in a hex, it could be eliminated by any enemy unit moving into or through its hex, and not just by advances after combat? Or can it only be eliminated by bombardment, assault, or advance after combat? If the latter, I assume you use the 4-1 column on the Assault Table.