Kodak used an antioxidant buffer bath for years as a stabilzer. It was sold as Kodak Ektaprint Type II stabilzer. I have a patent on a modified version which is now used by several other companies for films. The Type II stabilzer greatly enhanced the stability of color paper, sometimes by over 2 - 5x depending on conditions.
As for dye stability, I am quite familiar with the antioxidants in both the paper support (see patents by Venor et al) or in the coupler dispersions (see patents by Lestina et al). I helped develop the first color paper to incorporate the work of both of these people and others (see patents by Edens and VanCampen). I am familiar with the methods of testing and the reporting of them (See work by Tuite or Wilhelm or Kapecki).
The questions of testing conditions involve the use of 200 fc or 500 fc for fade tests under light, and what ingredients to add to the gas mixture and what proportions for the high temperature and humidity tests. These are under debate between Fuji, Kodak and the standards committee.
The most recent compilation of this was by Kapecki at the ICIS conference in May and discusses all of these issues and more. RIT has a very large lab entirely devoted to research on this subject.
I have been tracking the subject since I was first introduced to it in 1965, and I have seen data going back to the 40s showing the history of this subject as it evolves.
It is much too complex an issue to discuss here. It is like dipping a toe into the ocean and saying you are now an expert on marine biology.