See, if in their introduction, it said "Horse-Horse Fruit, Model: Bakotsu" or "Bird-Bird Fruit, Model: Itsumade", then yeah, we should assume they were normal, albeit Mythical, Zoans.
But just being called that, and the shared powers of regenerating fire and telepathy? That isn't standard.
But then, when Imu took all of Saturn's power back, that tied it that Imu is the power behind them, to the point they are basically his puppets.
While this makes Imu look quite intimidating, it made the Gorosei utterly pathetic because all their magic powers aren't theirs. Imu could choose anyone if he so wished.