The category I have in my mind is "sabotage%". The idea is you become imposter, and you sabotage something and fix it, but you have to do all of the sabotages in a specific map EXECPT for the two player related sabotages. Such as Reactor Meltdown and Avert Crash Course. (I think that is one of them, I don't play airship at all) Honestly, not expecting this to become a category at all, because the rules might be a little bit too much, but I am just sharing my thoughts :)

I really like this

not a bad idea

Timing would probably start as soon as you click the sabotage button to enter the sabotage map. NOT first input after selecting imposter, because you have to walk away from the computer to be able to enter the sabotage map. Another idea is that timing starts when the option to enter the computer menu disappears.

And the timing can stop the frame the sabotage turns off