What are ramifications on the Oxygen plugin if Schematron, Constraints, and Subject Schemes are integrated into Oxygen?

From the perspective of the SDL tools, what are the ramifications of implementing each of these features?

My feeling is that a Schematron and some quick fixes (QFX) won't affect the Oxygen plugin...but not entirely sure.

Constraints though I think are implemented via DTDs, which I'm sure would affect the SDL plugin for Oxygen.

Lastly, my feeling is that subject schemes probably wouldn't affect the plugin.

I need an expert answer to these questions about the affects of integrating a Schematron, a set of constraints, and a set of subject schemes on the SDL plugin for Oxygen.

 

Thanks for any help on this.

Jerry