Which president was nicknamed "Unconditional Surrender"?

From which school did James Buchanan earn his undergraduate degree? From which school did Chester A. Arthur earn his undergraduate degree? From which school did Benjamin Harrison earn his undergraduate degree? Which president was nicknamed "Old Tippecanoe"? Which president was nicknamed "Give 'Em Hell Harry"? Which president was nicknamed "Tricky Dick"? Which president was nicknamed "The Comeback Kid"? Which president was nicknamed "Old Man Eloquent"?