Q:

Drawing a Bezier curve from two vertices

The idea here is for the control points to have the same location as two vertices from a different object, so that when I draw the curve I want, convert it to mesh, and add it to that object, I can snap it into place with minimal effort. 
Also, some clarification on including one object into another so the snapping can take place would be nice. 

A:

You can snap to other object's vertices just fine..
For example, just enable vertex snapping in the header, then hold ⎈ Ctrl while transforming vertices to snap:

Once you have the curve positioned, convert it to a mesh with ⎇ AltC> Mesh and join it to your mesh object by selecting both objects and pressing ⎈ CtrlJ. Note that you probably want your main mesh object to be active (last selected, with yellow outline) when you do this, so the resulting object has all the object data, modifiers, and materials that your mesh object had.