The silver content of emulsions coated on baryta vs RC was identical, as was gelatin level, but the addenda was varied to allow for the absorption of the addenda by the permeable baryta. Generally, keeping was far better on the RC and the same was true for B&W. The surfactant and water content was different due to the different properties of the two supports.
The Type II stabilzer first used AEH, a type of sugar (a hepitatol), but this was found to be too variable, so it was changed to sorbitol. The sorbitol and the AEH increased the glass transition temperature of the gelatin and thereby provided a rather impermeable oxygen barrier. It made the prints stickier in humid environments too, and so it was recommended only for enlargements that were to be mounted not prints being stacked.
The type II stabilizer was also at a different pH than the normal stabilzer. They were both discontinued with the Ektaprint 2 process. At that time though, AFAIK, the sorbitol could double the light stability of any paper regardless of whether the antioxidant was incorporated or not. It even improved the stability of couplers that made dispersions with high glass transition temperatures (again see Tuite et al).
Photofinishers and professionals didn't want to work with the Type II stabilzer.
This work was published by Edens AFAIK. It was also discussed by Tuite in a presentation at the SPSE conference in Washington DC in 1988 (IIRC), where Henry Wilhelm gave his first presentation.
The only other recent references are the book by Jon Kapecki used as a text in the ICIS course and the presentations by Kodak and Fuji. That book probably does not mention the Type II stabilizer though. I forget offhand.