This puzzle had its genesis on Saturday afternoon, Nov. 9, when Peter Abide and I were on Discord, trying to co-solve a Fireball meta. Peter had come up with what we both thought was 100% for sure the correct metanism; alas, it wasn't . . . nor was the answer we finally submitted, truth be told. I liked Peter's idea so much, though, that (with his imprimatur, of course!) I created a meta using it. Here's hoping you enjoy this puzzle as much as I did composing it. Thanks to Peter for all his help with this one, and to Joe Ross, as always, for his formatting know-how.
NUDGE: An alternate prompt for this puzzle might be "What U.S. state completes the set?"