A and C:
A scarfed joint is simply a slightly improved butt joint. With no fibers going through the joint, it does not have the same strength characteristics as the surrounding material.
Your concept of an "infinitely scarfed joint" is very nice! However it precisely highlights the reason that a scarf joint would not be used: the weakest direction in a composite is in the direction that there are no fibers, i.e delamination.
In my opinion, a simple scarf joint cannot be used for this repair. There will need to be a significant lap joint most likely with some kind of reinforcement (either interally bonded to the composite or something similar to a riveted doubler plate).
The reason for this is that for a large area of repair, strains become more critical than stresses. And a simple scarfed joint will not be able to tolerate those strains (flexing due to flight and pressure cycles) for any significant time period.
I will be happy if I am proven wrong and learn something new, but for now this is my story and I am sticking to it.
I hope that we will soon learn the details of the actual repair method so that one of us will be eating crow for dinner!
Disclaimer: the above comments have not been reviewed for accuracy by the Society for Metalcentric Thinking.