What was the purpose of multiple species in the grand plan?

In a previous post there was some discussion on whether Neanderthals had a soul. Just one of many :) posters came to the conclusion (as did I) that they did indeed have a soul as a species that sought after spiritual enlightenment. Then the question was posed if this was christian-based or not. Now that is a good question. Just what was the purpose of having multiple species on this earth? Homo Erectus, Homo Sapien, Neanderthal. They all lived on the earth at the same time, and many other species preceded them. Were they all just part of a greater human experiment where God sat back to see which would become the ultimate survivor? Well, the Homo Sapien's won that battle around 25,000 years ago. Why did it then take another 19,000 years for God to reveal his eternal plan to Adam and Eve? Just having trouble reconciling all this with what is taught in the scriptures.

Did Neanderthals have a soul?

If man was created in the image of God, does that include all hominids? Does that include Neanderthals? Did all hominids therefore have a soul? If the answer to these questions is yes, then where is the record of these people? Would they not have the gospel as children of God?

Neanderthals were intelligent humans that had a social structure and practiced such things as burying their dead, and adorning themselves with jewelry, etc. Were they just an experiment of God, and never actually given a soul? How do we explain the fact that they lived at the same time as homo sapiens? When did homo sapiens start having souls? Did they always have a soul? That would mean that for 100s of thousands of years, there have been humans on the earth with souls, but they did not have religion until around 6000 years ago, and the Neanderthals never had religion, at least not the true religion of God based on Jesus Christ. How can this be? Does God only love some of his children and not others?