I think that we need to keep the definition of the tree of knowledge and the tree of life as scripture tells us it is, then all other scriptures will fall into place. .. The tree of life is symbolic of the salvation we are given from the death that unforgiven sin brings on us.
To my knowledge the tree of life is spoken of thrice in the NT, all in John's Revelation on Patmos.
In Proverbs, it is spoke of several times, all related to attention and obedience to God's speaking, word, wisdom (3:18; 11:30; 13:12; 15:4) In the fourth gospel, Jesus said, "For me, my food is to do the Father's will", then he said, "Even as I obey the Father's command, so should you obey my command."
So from this I can see that obedience to the divine word is giving life, and disobedience brings death.
Now, how does this relate to the Tree of Life in Revelation? Revelation 2:7 says, "Whoever has ears, let them hear what the Spirit says to the churches. To the one who is victorious, I will give the right to eat from the tree of life, which is in the paradise of God."
What do we see in the Garden of Eden? Many trees, good for food, fruits abundant. One was forbidden. The disobedience of God's command caused separation, condemnation, death. Now we see Jesus, obedient (eating food) and are told to also be obedient (eating food). Proverbs repeatedly shows this obedience to God's word as "the tree of life".
Now the Ephesian church gets the same charge: "be victorious". She has some knowledge of 'truth' of God's word but needs to love, to obey the Royal Decree, "Love one another". Love has left Ephesus, but if it returns (obedience to Christ's command to love) she will eat of the fruit of the Tree of Life.
Now we come to the two interesting verses at the end of the Bible, opening the last chapter of Revelation. In 22:1 we see a very available tree, growing along side the river of water of life, the street of gold, connected to the throne at the center of the universe. Fruit abundant, always produced in season (1 fruit per month - no 'dry season' here).
Then the "ethnon" which elsewhere in the NT is translated as "gentiles" get the healing from the leaves. Not, mind you, the fruit, but healing from the leaves. Some lesser access it seems. The kings of the nations get to walk in the light of the NJ, they bring their glory into it (tribute), and their citizens are healed by its leaves. They do not eat fruit but rather are healed by leaves.
Pretty interesting stuff