Both Emmanuel and Gaia symbolize the forbidden fruit of knowledge in different ways – this is foreshadowing of their eventual merging. The Fearful on Earth represents the Garden of Eden. When the Fearful left, the humans were "cast out."
Nald’s father works for a company that does robotic mining – one of their common tasks is doing archeological digs at various sites, and his crew originally discovered the white fluid. He was embezzling money and Magitech found out about it. They knew it would be discovered after Nald’s mother got investigated, and that his father would fall like a domino too.
The Saturday group does not hear about Mercury’s "disposal" until after they return to the Terran systems on Dragonstar.
It’s possible that Bernstein learned something about the human genome from the white fluid – because the virus could have left traces of alteration. Another possibility is that Bernstein didn’t know about the fluid, but that later Nald or someone else involved with the Fearful virus will discover its link to the human genome in light of Bernstein’s findings.
Pip did eventually invent a "stairway to heaven." This is some kind of neverending staircase type artifact deep within Midgard. More details later.