I've cut most stuff related to the other moons.
Moon - Io
Diameter (km) - 3660
Orbital radius (km) - 421,800
Orbital Period (days) - 1.77 (42 hours)
Gravity Earth=1 - 0.33
Day - 21 hours
Atmosphere - Oxygen, nitrogen, methane 
Europa and Callisto are tidally locked, with one face constantly turned towards Jupiter. Io rotates at double its orbital speed, so that from its surface Jupiter appears to rise, set, and rise again once for each orbit, an apparent day of 42 hours; this is caused by orbital resonance, another form of tidal locking.
Warmed by the immense heat of Jupiter, Io’s equatorial jungles have been compared unfavourably with those of Cambodia or the Venusian Hotlands. In fact they would be a good deal safer, if not for damage caused by the mishievous Slinkers and the danger of Blancha fever.
There are temperate conditions within 20° of the poles (references to this limit as the ‘twentieth parallel’ are incorrect but unfortunately very common; it is actually the seventieth parallel). These temperate zones are larger than they might at first appear, each having an area of more than a million square kilometres, but mountain ranges, glaciers, and other natural features restrict the useful area significantly. There are two polar cities; Junopolis at the North Pole and Herapolis at the South. Communication between these cities is by rocket or winged aircraft; flight is complicated by dense cloud and mountain ranges which extend beyond the usable atmosphere. Radio is almost useless, due to interference from Jupiter’s constant electrical storms.
Io is described differently in different stories, and there are some inconsistencies within the most authoritative source, The Mad Moon. Briefly, this story describes Io as a tropical environment requiring no special protective equipment; Tidal Moon (which deviates from the canon of other stories) describes the atmosphere of Io as “mostly methane” and mentions that the atmosphere of Ganymede contains ammonia. For game purposes Io’s atmosphere contains methane traces as a greenhouse gas, but it is too dilute to pose any problems for human visitors.
The Mad Moon states that Io’s day is 42 hours, the same as its orbital period. This implies tidal locking – but Weinbaum also describes Jupiter rising and setting in the sky. The best explanation is that Io spins twice as fast as it orbits Jupiter, so that its day relative to Jupiter is 42 hours.
If the geography described in The Mad Moon is taken literally, Io’s tropics are small and the temperate zones are larger than the USA, but it’s obvious that this is not what was intended. Confusion over parallels seems the most likely explanation – the main protagonist of The Mad Moon is delirious for much of the story!
OK, that's a lot of special pleading - does it seem reasonable, or should I just go with the first footnote and add "Several other changes have been made to rationalise conflicts in the source material"?
I'm not happy about making Io rotate, but there really seems to be no way around it that doesn't make a mess of the jungles etc.