CA GEN 8.5 and CA GEN 8.6 have the same schema '9.2.A6'.
Since the models are 8.5 modules, they can reside on the 8.6 Host Encyclopedia and for sure can be used on a 8.5 Toolset without an issue.
For additional CA GEN 8.6 features, please see this link to the CA GEN 8.6 Release notes for your review:
But, specifically, for new features, please see this documentation:
The following features and enhancements have been introduced after the CA Gen 8.6 GA Complete release: