Thats good sofar, that weeds out some things. I would still spray some shit around the cyclinders that are not firing correctly and see if it revs up and points out a leak.
If some cyclinders run fine, I would tend to think it isnt a crank seal leaking air into the case, becasue all the cyclinders would run like crud.
If the reeds were jacked up, and the carb is still sending the right air and fuel, wouldnt the fuel puddle up in the reed boot/case? Not sure now that I think of it. I am saying if it was stuck closed or partly closed the fuel would have to go somewhere when it was being slamed into the face of the reed.