It would seem that you can progress further into an entity than indicated by the entity structure listed in TCC.  This is some really great news.  The issue is that I needed to return the Agency when the hire type was going to be contingent.  But when digging down the application entity, you’re halted at Candidate,TalentUser,Profile,RecruitmentSource as seen here:

It seems that if you know the path to a related entity (including child entities) you can dig in and show that information, for example:
Candidate,TalentUser,Profile,RecruitmentSource,ParentSource,Description will actually return the agency name.