After you pulled them did you open a few so you could tell when they stopped? That could tell you if your humidity is correct for lock down and if it is infectious( black gunk). You can find charts on development so you can tell when they stopped. Sorry this happened to you, don't let it stop you though. Your ideas for sterilizing and trial eggs is good.I'm home almost all the time so I don't think there would be a power outage i didn't know about. I plan to mix a water/bleach mixture and spray down everything in the incubator then let it air dry. There has to be something wrong. I have only got one chick to hatch that has been in this incubator and that chick died right after hatching.
With all the money I spent on eggs for hatching I could have simply bought chicks.
I am glad i did buy some chicks though. I think i'm going to bleach the incubator then just get eggs from my mom to try a few at a time til i start getting good hatches.