I'm trying to understand how this affects the redshifting of extremely distant objects.
Pretty much any distant stars / galaxies we look at from earth are redshifted, which indicates they are moving away from us. However we know we aren't the center of the universe (where the big bang happened), but that any observer at any other point would see the same affect we see - everything far away is redshifted. This is why we think the universe is expanding - because everything distant is redshifted. Further, the expansion of the universe seems to be increasing, which has resulted in the theory of dark energy to explain why the universe is expanding faster and faster.
However, if the speed of light is slowing, wouldn't it result in the opposite affect (blueshifting)? Photons en route to us from other distant objects (and thus that have been travelling for a very long period of time) are now moving slower than they were at first, according to the theory of this article. If the speed of light is slowing, then that would decrease the wavelength / increase the frequency, which would blueshift, right? Further, the universe isn't just expanding at a static rate, but the expansion is accelerating, hence the theory of dark energy. According to this theory is that explained by the fact that c is still decreasing? If c is decreasing does that mean that the rate of time is also decreasing? Or must that not be the case or otherwise the speed of light would not seem to be changing?