Not The Saturday Prize Puzzle

NTSPP - 455 by Elgar
An Exercise in Futility

Three stages of an exercise in futility are represented in the grid. In eight clues, wordplay ignores one letter of the solution (Stage 1; the red squares are supportive upon arrival) and the definition is for the entered answer (Stage 2, upon return). The answers to ten other clues are too short for their grid entries, a situation solvers must rectify to represent Stage 3. The figure responsible for the exercise is represented by (i) the unclued answers; (ii) the blue cell; and (iii) the letters in the grey squares.