The new tweeters arrived yesterday, and I will be evaluating the loudspeakers over the next few days. The seller informed me that there is no need to send the original tweeters back. This gave me the opportunity to perform a limited amount of forensics on the tweeters, so I removed the dome/voice coil assembly (three screws) and inspected the voice coil. It appears that the transitional connection between the lead wire, and the VC winding wire had broken loose from voice coil proper. This was causing the discontinuity through the VC. It is very probable then, that the tweeter failures were due to physical shock as the seller was insisting. This means that the tweeters were very likely working prior to shipment which sheds a different light on many of the posts in this discussion.
Because of this information, I will have both loudspeakers checked over for any further shipping damage, now that they appear to be fully functional.
So, this appears to be resolved, however, I still had to wait 6 months before using these loudspeakers. Next time, I will immediately insist on returning the item for a full refund, rather than accept damaged or otherwise non-working goods