I am jumping in here a little late and have a few questions. Why would we ever think that Adam was not created mortal? Would he even have been a man if he were not mortal? We need not complicate things by getting to philosophical. It is very simple if we look at what the Bible says and don't venture off into speculative theology.
When God breathed life into Adam, he was physically and spiritually no different than I was at birth other than he started out as a man and I as a baby. The main difference is that Adam did not have the death sentence placed upon him yet and I did (because of Adam- Romans 5:12 ). That may rock your theological boat a bit, but consider it for awhile because it is very important in understanding many biblical truths and will clear up a lot of poor theology.
Also, I am glad to see a discussion where the word "death" in relation to Adam and the fall is understood to mean physical death (of the flesh). Somewhere along the way (around Augustine's time) this death was thought to mean spiritual death. It has caused a lot of confusion and makes Romans 6-8 make no sense. It has led us to this thing called the "sinful nature" whereby all we can do is sin because we are "spiritually dead".
Adam was given a body as it pleased God (I Cor. 15:38-54). This body was "earthy" and "natural" rather than "heavenly" or "spiritual". He compares it to a seed that is sown that must die and come back in a different way. We are sown in "corruption, dishonor, and weakness" but will be raised in "incoruption, glory, and power". What all that means I have no clue. I am sure it will be better than what I can come up with in my wildest dreams.
God designed us, including Jesus, to live in a "vile body' or "sinful flesh" so that the power to live righteously would not come from us, but only from him. "We have this treasure in earthen vessels, that the excellency of the power may be of God, and not of us I Cor. 4:7".
"Now this I say, brethren, that flesh and blood cannot inherit the kingdom of God; neither doth corruption inherit incorruption. (I Cor. 15:50).