She Definitely needs to be the one to choose.
And... Something that I didn't see any of the others flat out say (although USAF385 alluded to it) is that she should actually get a chance, if at all possible, to TRY each of the candidates on her Short List, as opposed to settling for something that feels good to fondle and dry fire at the counter. She may feel that she has to go with a Subcompact, but many of those can be a handful to shoot comfortably (ie: the PF-9, DB9, Nano, LC9, Solo, etc).
The Shield, LC9S and others that are Striker Fire feel great to Dry Fire, but to many (especially heard this from females) the recoil of the LC9S (and LC9 Original) are harsh. Of course, others say that the Shield's recoil is harsher than the LC9S... Hence, why SHE needs to actually shoot them herself.
My Wife went through an SR9c and PF-9 (going just by how good they felt at the counter), then later, Rented the LC9, P238 & P938 before deciding that SHE likes/shoots best (most comfortably) is the G26. Even though she likes my Shield, she doesn't like it enough to trade her G26 for it. After shooting true DAO pistols, trying a revolver was out of the equation completely.
Your Wife also needs to consider that if she decides that she likes the P928 or P938 (or other SA pistol), is she's willing to train with it Cocked & Locked, as opposed to carrying with one NOT in the Chamber? DAO and Many Striker Fire pistols can be carried with one in the chamber with no external Safety to mess with.
Then, of course... Does it come in Pink/Pink Camo?

Just kidding... Any of them can get Ceracoated to her liking.

Lots for her to consider.