The Cambion would be fine assuming the creature were the direct offspring of a fiend and a humanoid. They're the half-fiends of 5e. If the fiendish ancestor was... somewhere... back in the ancestral line, then you're really looking at a modified tiefling.
That said, if, as DM, you wanted the daemonfey to be a bit more than just a tiefling, you're well within your rights to base them on the cambion instead.