Crossword puzzle clue "letter entry"

Today, I tried to put a self-effacing three-letter acronym inside each theme entry. Turns out it works in any order except the one I want. ___

Letter entry

Letter that rhymes with its preceding and following letter

Words between a letter and a word starting with that letter

Letter for letter

A letter + smell + a letter + unbiased + a pronoun = ?

Word form made with the big letter depicted in this puzzle's diagram (this letter is entirely absent from the solution)

Greek letter whose first letter is silent