After a week of erratic behavior, I decided to clear out the birdhouse in hopes of new activity.
I took pictures as I removed the front of the house and used a spatula to remove the nesting material in one bulk. After removing the material, we placed it in a bowl and slowly dissected it and found no eggs whatsoever. That was a surprise. No egg shell remnants or anything.
So now the house is empty again. We hope that it will be occupied again and maybe will see a successful birth. Look for the photos at the link in the sidebar.