Sol System, What of the other planets?

We know of Terra's (obviously), Mars', and Saturn's statuses. What of Mercury, Venus, Jupiter, Neptune and Pluto? Are they just barren rocks (possibly the case for Mercury), or do they have more going on?

While i don't have references to hand, i do remember at least one of jupiter's moons being a shipyard dealio, unless i'm getting mixed up between saturn and jupiter. Built the big, angry, secret word bearers ship.

Jupiter had the Shipyards that built alot of the ships. Other than that I dont remember any of the other planets being mentioned.

I remember that at least one of Jupiter's moons was Terraformed, references wer in Battle For the Abyss, and Nemesis.

There were space colonies in the Asteroid belt, and probably near or in the Gas Giants.
Venus is an unknown, but possible. Mercury is nigh on impossible, you'd either have to move it, have a mobile colony on the nightside, or have a colony that can take really extreme temperatures.

Didn't Venus have some sort of forest on it? I think I remember it being mentioned in one of the books.

In Reflection Crack'd Fulgrim remembers a story of a warrior trapped in an invisible maze in the Erycinian Highlands of Venus...

A reference to Lovecraft.

In The Walls of Eryx

IIRC Neptune got colonized during the "Age of Terra".

Apparently Imperial forces fought on Neptune in the early years of the Great Crusade. Furthermore Sedna was burnt away by the newly formed warfleet.

The moons of Jupiter and Saturn were warzones in which Imperial forces fought against aliens and their human slaves.

Dark Eldar!? In the System Sol!? PURGE!!

I don't know about the Dark Eldar, the Horus Heresy book just mentions aliens.

I think it was Collected Visions that mentioned Dark Eldar in the outer-part of the Sol system.