@Fisherman: Evolution happens over millions of year for anything as it takes an entire reproduction cycle to make minor changes. Even if you said humans would evolve and that evolution would be guided, we've evolved to be omnivores in over 65 million years.
The WTBTS and most apocalyptic cults claim that overnight Armageddon happens and within 1 day you're perfect in the flesh unlike most other religions, including true Christians that claim salvation and resurrection happen in the spirit realm.
The Bible doesn't know anything about tigers because the writers likely never came into contact with even a depiction of one until after the destruction of the temple and exodus to Babylon in 586/587BC where even there they would've been exotic. As far as lions, the Bible doesn't clarify anything about the garden of Eden because it is allegorical, not literal. We do know that God clothed Adam and Eve in animal skins - an inherent reference that the writers expected God to accept the killing of animals for its properties but that is (if you take the Bible literally) diametrically opposed with what Isaiah claims.
Beyond the direct killers, the entire ecosystems is also built on the fact things die, scavengers, bugs, fertilization most of what you eat today is only possible because of stuff that died yesterday. Again, things the Bible writers wouldn't have a clue about, but nonetheless now have to be taken into account.