Just to throw out some potential lines people could say:
“For Leia!”
“We’re with you, Poe/General Dameron!”
“[insert callsign], standing by.”Callsign ideas: Phoenix, Ace, Phantom, Wraith, Red, Blue, Gold, Green, Wolf, Wraith, various planet names (like Naboo Fleet, Bespin, Ryloth, etc.). You could either say Leader or Squadron, or a specific number. Maybe people could think of some clever easter eggs to throw in at this point.
I think the “all wings report in” moment would be great for the reveal shot, as we hear all these people raise their voices in solidarity. Then throughout the battle we could get various lines like, “For Skywalker!” I do think add voices to the battle would definitely help make that incomprehensible number of digital ships feel more like real, living people joining the fight.
PS: Dibs on “Rogue Leader”
Talking about Easter eggs, maybe someone could impersonate Hera Syndulla/The Ghost (or just repurpose lines from Rebels)? It would also be cool hearing Mandalorians since Gauntlet and Fang Starfighters are seen.