Words: 72
Average Length: 5.19
Sometimes you just have to go with silly. Take common Latin expressions, “pun-ify” them, add some hopefully decent (and gently-clued) fill, and unleash goofiness upon the world (or at least the 150 or so Terrans who usually solve my puzzles). Explanations of the original expressions and alterations (spoiler alert) follow the photo.

17 Across: CARPE DIEM – “seize the day”
24 Across: ET CETERA – “and so forth” (ETA is common dreck fill, a/k/a crosswordese)
36 Across: ALEA IACTA EST – “the die is cast” – supposedly said by Julius Caesar upon crossing the Rubicon to invade Italy and begin a civil war. Kirstie Alley played Rebecca Howe, hence upon being cast in the part, 36 Across.
46 Across: SINE QUA NON – a necessary condition: “without which, no”. I realize that the universe of “classically-educated far-right conspiracy mongers” likely is a null set.
57 Across: NE PLUS ULTRA – “there is no better” – the beauty store in the answer currently is US-only, so hopefully non-US solvers can get this from the crosses.