I don’t see that animals didn’t die before Adam sinned in Genesis 1:29-30, 9:1-4.
‘Pre-fall’, the ‘ADAM’ may have lived a very long life (compared to today), but they were not immortal.
There would be no reason for God to be concerned that Adam would ALSO eat of the TREE OF LIFE (become as GOD’s or IMMORTAL) if Adam were already immortal.
Pre-fall, Adam had no REASON or NEED to KILL any other creature, as ADAM was in a state of ‘innocence’. Once Adam chose NOT to ‘listen’ to ‘God’, he was no longer in a state of innocence, and the results of that are listed in the Bible. Adam and Eve chose not to listen to God and procreated whenever they wanted to, and not ‘in season’. This is why women experience pain in childbirth.
All of this ‘fall’ didn’t occur in one day, it happened over a long, long period of time. Writing that into Genesis would have made the story MUCH MUCH longer and more complicated, and the POINT might have been missed (and is still missed by some).
As far as the animals (and even ADAM), if you fall off a cliff, unless you are immortal, you die.
Gen. 3:21, God provided coats of fur for Adam and Eve, 1st Blood Sacrifice because of sin.
bobo