Chad;

It is the implementation of the business object pattern.

Term:  Business Object:

An object that implements business logic and/or business data.

Business data and business logic are implemented in coarse-grained objects called business objects.

In J2EE, business objects are implemented as session or entity beans.

In some cases, a business object could be an arbitrary java object that provides some services.

See attached document for class and sequence diagrams

I do think that these  diagrams must answer most of your questions.

We might implement the business object using the composite entity pattern (you are right) or DAO or other different implementation.

Regarding your question ?Can the Presentation Tier directly
instantiate and use "Data Objects"? ?

We always use the business delegate pattern to decouple the tier and hide the implementation details. It is better not to use it directly from client tier (my opinion).