KB's fuse corroding due to the moisture from the steam makes no sense, there are a number of highly conductive and corrosion resistant metals used to make droids and starships; platinum and tungsten have both been mentioned in various Star Wars works as being used in droids & cybernetics: both are highly corrosion resistant. If servomotor fuses corroded that easily then droids would be very limited in the locations they can travel. Separatist battle droids were able to operate in high moisture environments for long periods of time, R2D2 even spent periods of time completely submerged under water without his fuses corroding. However, KB comes from a planet that has been deliberately isolated for at least several generations; At Attin may have lost the knowledge of utilizing these metals or it may have insufficient resources to use them in human augmentations.
When the kids are knocked off the tow ship and fall onto the ground, both the snow and some of the rocks/debris compacts down under KB's hands and knees as she gets up, but then the indentations made by her immediately return to their original shape. Making it obvious the ground and rocks were actually just a disguised rubber pad to cushion their landing.