I'm not sure what the rasion d'être could be for the 42.5mm. That is not THAT far removed from Fuji's nonpariel 35mm in regards to focal length or aperture width. And the price is not significantly different enough to give up auto-focus.
The 24 may find some adherents for the low price point paired with the wide aperture. I'd need to see some samples though. Wide, cheap and great are rarely used in the same sentence.