Planet "b"
Three planets have been discovered. The "b" planet has a mass at least 1.935 times that of Jupiter, and an orbital period of 60.94 days. Though this is the outermost of the three known worlds, it is still embedded deep within the tidal braking zone. This braking zone would tend to halt the rotation of any world, just as our moon holds only one face to Earth.

Planet "c"
Planet "c" is a bit more light-weight at a minimum 0.56 Jupiter masses. Its orbit is a great deal more elliptical, moving it from cold to frigid distances from its parent star.

Planet "d"
Newly discovered "d" has a minimum mass of 0.023 times that of Jupiter. That would make it 7.3 times as massive as Earth, if its orbit is inclined at 90° (edge-on). This would make it half the mass of Uranus, the Solar system's most light-weight gas giant. Its circular orbit would help its habitability, or that of any moon it might have. However, its orbit is well within the hot edge of the eco-zone, so even a moon would remain too hot for habitability.

New Earth?
The eco-zone is embedded deep within the zone of significant tidal braking for Gliese 876. Any world close enough to have sufficient warmth would be tidally locked with one side forever facing its sun. An Earth-like would could still exist in this system, but it would have to possess a close moon or twin world to force it into a healthier rotation. Such a configuration is thought to be possible, but rare.