I would try to talking with her more about the chamber being unloaded and having a manual safety
. Until you guys get this issue hammered out I think you're going to have a tough time finding a gun.
In fact, I wouldn't continue discussing which gun to get until this issue is resolved.
Anyway, have you guys given the S&W Shield any thought? It's capacity is a little low, but should be easy enough to shoot. It also has a manual safety.
You may already have the answer! His and Hers Bersas/PPKs. She is probably familiar with yours so training will be a snap. It has a manual safety, and she could always keep the hammer forward (no slide racking) instead of having an empty chamber, so she would have that redundant safety-safeness she is looking for.
Finally, there are the old, all-metal S&W handguns like the 5906. If the size will work for her then you have all of the other requirements. Minus that first double action trigger pull will be heavy. Again, I come back to the safety and unloaded chamber