I moved like next to Antartica so I'll have little free time these days. I also have no internet in the place I'm staying but I've made some progress.
Since there's no way for me to add new damage types, I'll just rename them and adjust the damage/armor values.
Laser damage will be replaced by Shock damage, which will cause lots of damage to machines or aliens like floaters, since they are part machine. Laser weapons will deal heat damage but really little, since I made most characters weaker to that damage type.
Shock weapons will be the first researchable human energy weapons instead of laser weapons. These guns will fire bolts of electric current but will have limitations. There will be no ammo for them but their range will be limited. After researching shock pistol, rifle and cannon, Laser weapons will be available.
After that, I will add an extra research after plasma weapon adaptation, which will allow players to manufacture ammo types for plasma guns, one that will deal heat damage and another for shock damage.