Actually my original thought on all this about two years ago was very simple.
1 + z = ke/ka = Q(ta)/Q(te)
a = absorption
e = emission
z > 0 redshift
in dS metric
Q(t) = e^t(dark energy density)^1/2
in the accelerating expanding universe retarded radiation toward the future is redshifted, advanced radiation toward the past is blue shifted.
Note units are h = c = G = kB = 1.
The redshift at our future dark energy horizon a finite distance from us is infinite - this is effective absorption - vanishing of the real photon to almost zero frequency ( actually 10^10/10^28 ~ 10^-18 Hz).
In microscopic terms, the Hawking mechanism - effective geometrodynamical field ionization of virtual electron-positron pairs into real pairs with one particle beyond the r = 0 observer-dependent horizon and other particle inside it - effective plasma charge neutrality on both sides of the horizon - cause the return advanced signals back to the r = 0 emitter inside the cosmic horizon.
From the principle of horizon complementarity we don't give a hoot what an LIF at r ~ /^-1/2 crossing the horizon sees. What only matters is what we see at r = 0. We each see a consistent picture, but it is not the same picture.