Good post.. but... Uranus is a gas giant. There is no scenario where it could be imagined as a terrestrial ice world and still make any semblance of sense. However, it's moons would be fine. People may argue "space magic" or "venus has trees" but those excuses fall short. The space magic that gave venus trees makes sense in a farfetched scientific way. The organic material required for life are present on venus, however the runaway greenhouse effect on the planet have heated it to temperatures that far exceed anything that can support life as we know it. There may presently be extremophiles on Venus, though it's unlikely. A certain amount of imaginative "space magic" can be applied here to stabilize the greenhouse effect and give the planet a proper magnetosphere to ward off radiation from solar wind. Boom. Acid Rainforest. Uranus though, not nearly as simple and muuuuch more theoretical. First you would need to stabilize the extreme 90° axis tilt. Then, if we're going for an earth like planet, you would need to blast off the gaseous layers while leaving a little left to cover the bare core. This purging of atmosphere would cause the core to cool to an extreme -300°F. It would need to be superheated with solar mirrors, strong greenhouse gases, or comet bombardment like earth experienced in its early stages of development. Even if this could be done, stripping the atmosphere of a gas giant would dramatically alter it's overall mass This would completely -blam!- the orbits of all the other planets in the solar system, wreaking havoc and possibly causing collisions. It would make much more sense to 'terraform' or set up shop on the gas giants moons. /End science rant