All of those modification times/users should be in a separate audit trail table, which likely will look like an EAV table. That's OK because it's tracking the h

All of those modification times/users should be in a separate audit trail table, which likely will look like an EAV table. That's OK because it's tracking the history of updates, e.g. (time, table_name, column_name, old_value, new_value, changed_by). The current (rather than historical) values should not be in generic EAV tables because putting data of different domains in the same column subverts both the relational model and the DBMS's indexing capabilities. If the point is to label telephone numbers with a role, then a person_id, phone_number, phone_number_label table should be fine.