The Many Planes of Leronia

Hello!
This is where I'm developing my personal campaign setting for Dungeons&Dragons 5th Edition. The general concept is to create scientifically sound justification for most everything in the world. Whether it's the way the landmasses form, the climates of those landmasses, how the arcane functions, or how species developed and where they're commonly found. No "There's bugbears in these woods because that's where they are," scholars would have a fairly educated guess that they arrived on the continent from a land-bridge that's disappeared, and they adapted to the pine forests in the northern part of the country.
Some interesting ideas of note that I plan to implement:

• A fine line between intelligent species and animals
• Divergent/Convergent evolution of the player races giving them near identical abilities, being the reasoning for overhauling racial stat bonuses
• A possible history that chronicles the change from ethno-states to very diverse nations
• Given spells involving the etherial plane, the idea of multiple planes of existence will be heavily inspired from Eberron. I'm not exactly sure what I plan to do yet, but planes will be involved.