This is closest to my preference. In particular, I’d like to see the relevant fields moved into BaseChangeableOpenmrsData and BaseChangeableOpenmrsMetadata (and have those classes implement the Changeable). This work is mostly done, i.e., they were deprecated in 2.2. That should at least take care of the domain objects which are not changeable (and, as an added bonus, actually reflect this in our API).
However, I don’t think there’s a single one-size-fits-all solution to this. For instance, Privilege and Role should probably actually have the creator / editor / voider properties for auditing purposes, but that probably requires a Liquibase changeset to handle properly (i.e. to add a date created / creator at a minimum to the records in those tables).