Crossword puzzle clue "letters that come between r and v"

Starting a project ... and what the letters between the starting and ending pairs of letters in each starred answer are doing?

Letters that come between R and V

Yankees manager of the '70s between two Billy Martin stints and of the '80s between two Gene Michael stints

It may come between money and everything

"Come not between the dragon and his wrath" speaker

It can come between Clinton and Rodham

They come between fives and twenties

Letters between a name and an alias: Abbr.