Days after a billionaire pledged to pay the collective student debt of the entire 2019 Morehouse College graduating class, euphoria was not the only emotion in the air.

On Morehouse’s Atlanta campus and beyond, administrators, students and parents — and no shortage of philanthropy experts — have spent the last few days wondering exactly how Robert F. Smith, a titan tech investor, would fulfill his promise to 396 graduates. The surprise announcement was both an extraordinary gift and a complicated one.

At the end of a graduation celebration on Sunday night, Shaquille Lampley returned to his dorm room on campus, opened the computer and stared at his student loan estimates. They totaled more than $200,000 in loans taken out by his mother, covering six years in school. “I just kept looking at the number and thinking to myself, this would cripple me for life,” said Mr. Lampley, 24, who earned a degree in sociology. “I am so grateful and still in shock about this gift, and now I have so many questions about how this will be processed.”

[An average black graduate has $7,400 more in debt than white peers.]

Among the questions: Are all student loans included? Does the pledge include loans taken out by the graduates’ parents? What about gifts from home equity loans?