4 hole is becoming more and more popular on road, also.
Wow, that is an interesting crankset indeed. I'd probably replace the whole crankset, at least the right arm, perhaps casually look for replacement hardware for the Aero
#5 afterwards if you wanna go back to original spec.
To replace the cranks you'll have to find the bottom bracket spindle length so that you can find some cranks that will fit.