I had almost the same problemish when I really thought over how I was going to handle Tres. Normally I try not to app canon characters that have had very close relationships into small canon casts, but in this case, it works out for me to play both Abel and Tres. Abel is no Wordsworth, but because he's a machine, Tres can't do ALL of his maintenance himself.

So I'm probably going to have Abel taking care of those responsibilities in mostly handwavey form just for convenience's sake, because robot.

If you did decide to try to app her at any point, I have at least two PCs on my own roster who are decent with robotics and could potentially make her a new key and take care of that, being ... Spock, and Urahara. Who are both engineering-types.