If someone ever decides to mod this in, balance it however you want.
Androids
Somewhat similar to how they work XCOM:Apocalypse(Immune to PSI powers but extremely low stat gain), and being zombified should instead kill them instantly. Should be balanced by taking up HWP space, cost, availability, requiring manufacturing(maybe E-115), etc. Cannot use PSI, but is completely immune to it. Cannot panic.
The man that died twice saving the earth
Dead soldiers should be able to be rebuilt, but there should be balancing. Rebuilt dead soldiers(Miniature MEC Trooper? Robocop? Robo-Canuck?) don't take up HWP space, but should be more expensive(money/alien materials/other), and they are resistant but not immune to PSI. Can be zombified. Unable to use PSI. Resistant to panicking from soldiers being killed/alien psi panic. Stat gain still slow. Can only be brought back from the dead and rebuilt as a cyborg once, and then they die(should they explode on death?)
Androids should be less expensive(compared to rebuilding a dead soldier), but take up HWP space. Rebuilt soldiers don't take up HWP space, but are more expensive in terms of money and manufacturing than androids. Both Androids and Rebuilt Soldiers should have zero PSI skill, and cannot use a PSI Lab. Androids will be completely immune-ish to PSI, while rebuilt soldiers should be resistant. Androids and rebuilt soldiers should probably have higher health and no recovery times in exchange for poor stats(Firing Accuracy/Time Units/Health/Other).
