MIni theory:
Lunar biome: Element origin
Proof: Alien dinos, Reapers (literally called xenomorphs in the game files) and seekers. Dunno about the whales
The moon that is shattered is leaking blue everywhere. Blue can be associated with tek tools, element dust, etc. Heck, there is even element gas and element vents all over the shattered moon, meaning that element definitely IS here.
About the tek dinos: This is a simulation and not everything has to be 100% accurate. These tek dinos must be here to show the link between tek and this planet, which has a heavy element presence.
And if this planet is really shattered, one or two of these moon rocks with element could've crashed down to earth, spreading itself to civilization.
Also, ARKS are meant to preserve life and spread it back to earth, and on AB Reapers and seekers are definitely present. This doesn't necessarily mean that they needed to ORIGINATE on Earth.