Crossword puzzle clue "each one in this puzzle has its year in parentheses"

Each one in this puzzle has its year in parentheses

What's clued in parentheses for each of four answers, and found in corresponding sets of puzzle circles

Like each answer in this puzzle - also each word in each clue - in length

What Santa puts on each year, with "a" (complete the puzzle to reveal seasonal refrains in the circles)

Each of the four longest puzzle answers has two pairs of them

This completed puzzle has 10 of them, each three letters long, reading diagonally

What each of this puzzle's longest entries has two of

Newsstand buy, for short—one begins each of the four longest puzzle answers (and also ends the last one)