You should be covered on the biopsy as this is considered an outpatient diagnostic laboratory test, covered under your medical plan.

The root canal problem. A root canal removes all the nerve so it would not be unusual for there to be no pain from the tooth. The red area indicates an infection and this may not create pain either, especially if you are on antibiotics that are reducing the infection.

If the failure means the tooth structure is bad and a place where infection can enter the tissue area then that does require fixing, not sure what but glad you are getting that fixed sooner rather than later.

Good luck.