Actually, didn't Greg technically canonize it a while back in one of those 'Ask Greg' posts? I think he said it was less that they couldn't/didn't feel love than it was they would've had no frame of reference for the emotion, and no real drive to follow it during the GSR years, but once they began living on Bara Magna they'd actually have something to compare said emotions to, and begin to understand what they meant.
Though from my own understanding their version of love would still be much more different than the Bara-Magnians own, due to their species being more mechanically than organically, and thus lacking certain... instinctual drives such as the Bara Magnians would have.)
It went something like that didn't it?
Also, bloody beautiful build mate, love the distinctly different body types you gave the both of them, and the way you designed their added 'plant-wear'.
Real nifty grass/frond skirts, both in build and look.
Additionally: EY! They have pupils! And also eyelids of a sort for at least one! Nice!