My main suggestion about destroying the idol is to keep your game on the normal or slow speed. I was trying to do it on the fast speed and I couldn't control the heathens. They were coming out too fast and rebuilding too fast and too often. Once I changed it to the normal speed I was able to get my builders to complete the task at hand.

As for cleaning up the masoleum, you have to keep those builders on the job. It's a nasty job and they don't like to do it so you have to keep pushing them back to the job at hand. And also pushing the kids out of the way. It's a long job and it's boring bit keep after it. Put the game on pause for a while and go back to it.