Why not just ask him directly who the kid in the photo is, instead of this roundabout way of asking a coworker? He's most likely to know. Like, it's not even creepy to be curious about something like this.
I'd say workplace girl should be able to draw the conclusion "oh, then he has an old picture of his daughter on the phone", because that's a normal thing that does happen.
But then husband is completely unable to keep referring to reincarnated wife as current wife, so maybe there's crazy in the water in their workplace and it turns everyone into idjits.