Radiation on Pandora?

[Human No More]

Exactly.
Anyone who said haemoglobin is magnetic has very little understanding of it and just knows 'well, it contains iron'.

Yes, the mountains float due to the effects of magnetic fields on superconductors, but even if they DID float ferromagnetically, then the magnetic field would need to be a lot stronger than it already is, but still nowhere near as strong as artificial fields humans are regularly exposed to with no problems.