What I've been implying but never really stating is that the new planet everyone is living on at the end of Xenoblade is Mira. This is the only way things work out, since Earth in Xenoblade X is the same as our Earth today (with LA and China and stuff).
People have been finding some features in the geology of this planet that could suggest this.
The first image is more convincing, however. If it is to be believed that this planet was previously uninhabited, then where would that massive giant ring come from and what purpose would it serve? This is a very strong finding since at the end of Xenoblade, the two titans sunk.
Another possible indicator that Mira is the world of Xenoblade is the huge size of many of the creatures.
Something that is key is at the end of Xenoblade, Alvis and Shulk created an entire new universe (this happens even though Shulk said "world" because he does not have a bigger concept).
The plot of Xenoblade X, which appears to be a war between alien species, may have even been hinted at in the end of Xenoblade.
--Alvis: "Shulk. This new world is boundless. It is home to not only you, but many forms of life. I can see it. In this world, all life will walk towards the future hand in hand."
--Shulk: "One day I hope I can meet them all. The people of this endless world."
--Fiora: "Me too. We will. I know it."
--Shulk: "We'll meet them, and whatever happens, we'll face our future together."
I will restate that 'World' refers to 'Universe.' Alvis even says, "This new world is boundless." When he talks of other forms of life in this boundless world, he refers to not just life on that planet but also aliens. Shulk and Fiora are sure they will meet that life, so in Xenoblade X maybe they, or somebody descending from them does.
Why we do not see any Homs in the trailers is the same reason we did not know "X" is "Xenoblade X" from the beginning and that nopon are in the game. Nintendo has been pulling a sort of secrecy ploy with their recent big titles. They slowly reveal things to build hype. It's totally possible that some of the humanoid characters we see in the trailers are homs, since there is no way to distinguish them from humans. For instance, the girl with the Monado hairpins could be a hom.
So in my opinion, the nopon, homs and other species of bions/mechonis are the original inhabitants of Mira but then humans land. The humans have the goal or rebuilding humanity to its former glory as is a theme present in the E3 2014. "This is the duty of Growth." Maybe on their quest for gaining control of the planet, they stumble upon the homs and do not accept them so the two have conflict.
Now this is just speculation on Xenoblade X's storyline...
Main characters really want to prevent the war between the species. This is based off of somebody from the E3 trailer saying 'stop fighting!!' This could be why the Nintendo person said they share a lot of the same philosophic ideas. In Xenoblade, Shulk wants to know why the Bionis and Mechonis have to keep on fighting and strives to stop that fighting. Homs can fight in altered faced mechon and humans in their doll mechs.
