>Have been replacing a queen in a queenless hive. I cut out all the queen cells and added the new queen.
Why didn't you just let them finish the queens they were making?
>Checked in 4 days and she was still in her cage, the girls had built 4 more queen cells and capped them (in 4 days). Removed cells and going to wait 2 more days.
?
>#1 Is it common for the workers to continue to build queen cells after you put in a new queen?
Not if she is making enough pheromones.
>If I release her will they kill her?
Are they biting the cage?
>#2 Is it common for them to cap a queen cell in 4 days? (there could not have been eggs there, but very young larve)
They can start with a hatched larvae and yes, they would cap it four days later.
http://www.bushfarms.com/beesmath.htm