Were the twins identical or not? I know somebody said they had identical genomes but they never actually used the term "identical twins". Also I find it hard to believe that a scientist had an identical twin who was a marine.
How do you go to the toilet when in a pod operating an avatar (not to mention being paralyzed by a spinal injury)?
There was a brief mention of Pandora having low gravity but they never said how low. Everything seemed to fall at normal speed.
How long were the days on Pandora? Also being a moon of a gas giant, you'd expect there to be frequent, and possibly long, eclipses (from the planet but there were also other moons) and the planet shine would often make the night rather bright. Perhaps Pandora's rotation locked and all the action took place on the side facing away from the planet (I don't remember how often the planet was visible in the sky). I've thought about these things because one of the short stories Dragon Knights is based on was set on a moon of a gas giant and I did work a strategically timed eclipse into the plot.
None of Na'vi seemed to be pregnant. Isn't pregnancy obvious in them or don't they reproduce very often?
What was the toxic substance in Pandora's atmosphere (obviously it wasn't that toxic as humans sometimes survived breathing it for several minutes)?
How did those mountains float in the sky? I'm guessing it had something to do with unobtainium but I'd like a bit more explanation.
What exactly is unobtainium and why do people want it so much?
Where were the cute flying buffalos?
