After thorough investigations I believe to have solved the last mechanical challenges to make full control of the typewriter feasible. (in the least invasive / visual way)
cartridge return can be done by rolling up a string around the corner and released after it is done OR a motor with gears right behind it and raising the bar for the tabs to connect with the gears there (less hidden)
New Line: stepping motor, gear and belt to be able to sit on the cartridge that slides left and right.
key hammers get stuck: not enough power in the spring that was used to pull them back, can be easily achieved through extra weight on the hook of the spring.
Now looking for an adjustable power supply, breadboards, etc. Will probably go and check out a hacker space here in Toronto.