Re: c is calculable
I can think of at least one way the speed of light could have exceeded the expected speed within the early universe... if it was re-emitted but due to time length/iteration/quantum uncertainty limits did not interact as often with particles. It could have "skipped" particles, due to them being so close together? Then it would not be limited by re-emission as it is now in water/glass etc... due to the early universe being so dense.
Though it may just be me who is dense.