767Capt
Perhaps the issue is distraction.
There were two or more simultaneous missions underway; the FIRST should have been flying the sector safely. The line check was secondary, and the #1 RA threw more distraction into the cockpit, probably compounded by the extra crew.
The FACTS are - whatever the background and flying record of the crewmen, and whatever the autothrottle problem (including RA), allowing T/L's to remain at idle for 100 seconds in approach configuration with energy rapidly decaying, simply tells me that nobody was minding the store.