EARTH is not paradise by decree or by reward. It is paradise by arithmetic. Every soul that completes the ladder has spent centuries in forms that made self-interest structurally impossible — the ant doesn't have an ego to protect, the tree cannot move toward what it wants. By the time a soul arrives in human form for its final chance, most of the damage has already been metabolized. The fork in the road is the last test because it is the only one that requires a genuine choice. After that, there is nothing left to burn.
The closed ecosystem in Jack's living room is the novel's small version of this argument. A system that sustains something fragile requires 112 days not because 112 is an arbitrary number, but because the system needs that long to demonstrate that it can process its own failures without collapsing. The axolotl is what you introduce when you've proven the system can hold it. EARTH is what you arrive at when you've proven the soul can hold it. The number is the same because the argument is the same.

