I'm sure that each of the 8 unclued lights is intended to produce just one homophone, and that although 10 down could be plural, 'are' is not the intended one. 'Esse' (pronounced ess-e) would have to take its literal Latin meaning to be a possibility, and require 1 across to cover just 2 letters (? XL) I feel JUDGE is ruled out by 28 down, so you must take your pick between the other 2 (see above). That leaves 2 or 3 letters to be covered in 1 across. LEADING NOTE is too vague as a definition, as it could refer to any note, and in any case it is singular (see above). My money is on LEADING ROLE for 'effendi' (FND).