To close this discussion, just updating on the fact that I have managed to implement the reparametrization for the Rebo potential as given in L. Lindsay and D. A. Broido in Phys. Rev. B 81, 205441.
I will push this through Github as soon as I finish the manuscript in the coming weeks. This includes an updated CH.rebo file and a (hard-codes) value change in the pair_airebo.cpp (T0 parameter) file.