When do the sub-titles ("determination to fist", etc.) for each season of Symphogear get dropped?

Question

Each season of Symphogear comes with a rather amusing sub-title.

• Season 1: "Meteoroid-falling, burning, and disappear, then..."
• Season 2 (G): "In the distance, that day, when the star became music..."
• Season 3 (GX): "Believe in justice and hold a determination to fist."

When, if ever, are these lines uttered in-show?

Answer 1

Meteoroid-falling, burning, and disappear, then...

This is just the title of S1E13 - 「流れ星、堕ちて燃えて尽きて、そして―」. This refers to how, after Hibiki/Chris/Tsubasa attacked the chunk of the moon knocked loose by Kadingir, the resulting fragments fell to Earth as shooting stars, i.e. meteors. (Really, the title should probably have "meteoroids" plural. Crunchyroll wisely titles S1E13 as "Meteoroids Falling, Burning, Disappearing, and Then...".)

I'm not aware of this line actually being uttered anywhere in-universe.

In the distance, that day, when the star became music...

This is a direct translation of 「遥か彼方　星が音楽となった…彼の日」, which is the first line of the second and seventh verses of "Gyakkou no Flugel", the Zwei Wing insert song from S1E01.

Naturally, this line is also part of the lyrics to "Niji-iro no Flugel", the reorchestrated version of "Gyakkou no Flugel" that was used as the ED for S2E13 and S3E13.

Believe in justice and hold a determination to fist.

This is almost certainly an attempt at translating the title of Hibiki's first insert song from G, 「正義を信じて、握り締めて」 "Seigi wo Shinjite, Nigirishimete". A more natural translation would be something like "Believe in justice and hold it tight". I haven't the slightest idea how "determination to fist" came about, and I'm happy to award a bounty to anyone who comes up with a compelling explanation of how they bumbled their way into this translation.