Is it possible to teach slaves traits? Like if you homeschool someone enough, they gain the nerd trait, or they gain the submissive trait if you lock them up long enough? If not, can we please add something like that, i've been save scumbing for nearly an hour trying to get a techie nerd for hacking doors.

You have to hack the doors, followers are useless for that

You look for an educate button or something when in the npcs menu. You also can't do it very late in the day and it will give you a list o certain stats you can try to raise. 

 The codes appear to be hard-coded and don't change from what I've seen. so if you are save scumming anyway:
save the game
go hire the 4 mercenaries with the techie trait (Aike Hayashi, Dexter Colt, Doyle Bekker, and Samuel Spartan)
make them your followers
go hack the door and write down the number
restore the game
go to the door and use the number you wrote down.

If you're gonna do all that, I'd prefer just saving some money and buying the computer in the general store, and the one in Modules in the house, and read a skill book or two.