Well, its about time.Boy am I late to this party.

So, the Lenikravitz system has this ringworld AND a water world?? Either that's a very crowded little habitable zone, or this ring is a LOT less than 30 million kilometers - in which case why mention the 30 million?
Gotta say though, flat expanse in vacuum under bright light - seems like an ideal place to build solar-powered factories.
It's a bit odd gravitically agreed. The ring would affect the planet.
If the planet is inside the ring, perhaps Grandfather intended it as the first seed of material. Now thousands of years the decendants of engineers (Chippers) are there.