1.) yes
2.) yes
3.) Move the whole nest, if possible. Mine are built through the coop walls, so it's not possible.
4.) Yes, you need to keep her from returning to the old nest location.
As the advertising always states, your results may vary.
It's worked so well for me this year, I...
Could they be laying somewhere else and you're not finding the eggs? The broody could be in the "favorite" nest and the others decided to find a "second favorite" spot.
When I've got too many broodies parked in the nests, everybody else decides to lay eggs on the coop floor.