I do not really understand how it is possible to get from “originally no death or carnivory” to the familiar carnivorous ecology post fall, without an extensive second act of (re)creation, be it by God or Devil. The children of Adam can get from gardening to sinning and killing without any change in morphology essential; only a bad attitude required. Animals, though, must feed as they are adapted to do, it is not just a change of appetite involved. For so much of the animal kingdom, nearly everything about them revolves around feeding to stay alive, or not becoming a meal. Their camouflage (often extraordinarily eleborate), stealth and appearance, vision and placement of their eyes - forward, sideways, on top of head to hide in water, dentation, venom and poison, speed, claw and talon, digestive tracts, social behavior, defenses of ink and quill, on and on - their role in the food chain largely defines the animal. Would a pre-fall lion look rather like an antelope? Would not even a child intuit that a T-Rex is bad news?
BTW, this thread delved more into death and the fall: