I'm not sure Soong-type android applies to Fred, and I'm certain it doesn't fit Dahj.
Unfortunately it's not clear just how indistinguishable from life Fred was. We know Dahj and the other Coppelius synths passed for human. Even Picard, though there was clearly some differences. With Fred, though, Culber pulled up the graphic of his internal works, and it didn't look like he's a meat robot. However, if he was closer to Data and Lore, I don't think getting shot in the chest would have been enough to kill him. Data's detached head was stuck in a mine on Earth for about 450 years and worked just fine after being reattached to his body, but I get the distinct impression that Fred wouldn't take decapitation so well.