Thank you, lacerto. Right now, it's Print On Demand, not offset, if that makes a difference in CMYK conversion specs.
To review, at the initial creation of the document, if I toggle to the correct Color Profile, and select "Assign" in the Document Setup, then manually define all K100 text within the document, and leave "Convert image color spaces" in the Export options unchecked, then the graphics should remain true to color and the K100 text fully black in the final export. Is that correct?
Another curiosity: If I chose for Publisher to Convert placed images to the Color Profile in the Document Setup, but then also told it to "Convert image color spaces" to the same Color Profile in the Export option, is that redundant? Would it cause any problems in the conversion?