Basically writing this down for “what I should nuke in FireShell” purposes, but I figured it might be a minimally useful post. Bolded entries are essential to the GUI.
0x01 - 0x49: Shop, Arena text
0x4A & 0x4B: Suspend
0x4C - 0x58: Link Arena, Trial Map, Data Clear text
0x59 - 0x1AE: Support conversations
0x1AF - 0x22A: Character descriptions
0x22B - 0x25A: Class descriptions
0x25B - 0x278: Stat screen descriptions
0x279 - 0x347: Weapon/item/use descriptions
0x348 - 0x351: Weapon level/support page descriptions
0x352 - 0x374: Unit, map menu command descriptions
0x375 - 0x395: Prep. screen, storage descriptions
0x396: "There are no messages for this menu item."
0x397 - 0x39D: Status screen descriptions
0x39E - 0x3A6: Battle preview descriptions
0x3A7 - 0x3B2: Misc. system text
0x3B3 - 0x3DC: Team builder Link Arena
0x3DD - 0x3F2: Misc. system text
0x3F3 - 0x48E: Weapon/item names
0x48F - 0x4DB: Class names (Duplicate names for both genders in vanilla)
0x4DC - 0x55B: Character names
0x55C - 0x58B: Chapter names
0x58C - 0x5B4: Chapter names w/ numbering (Lyn & Eliwood modes)
0x5B5 - 0x5D1: Chapter names w/ numbering (Hector alternates)
0x5D2 - 0x5E1: Misc. chapter names
0x5E2 - 0x621: Tile names
0x622 - 0x65B: Options screen text
0x65C - 0x6BB: Chapter goal entries
0x6BC - 0x70E: World map text
0x70F - 0x71B: Item effect text
0x71C - 0x735: Scrolling help text
0x736 - 0x74F: “You can’t do this” text
0x750 - 0x760: Unit action pop-ups
0x761 & 0x762: Drop item? prompts
0x763 - 0x78F: Transfer data, Link Arena text
0x790 - 0x7A6: Tactician input text
0x7A7 - 0x7FE: Death quotes
0x7FF - 0x812: House convos (generally regarding the tactician and strategy hints)
0x813 - 0xF60: Main story text
0xF61 - 0xF6E: Ranking screen text
0xF70 - 0xF85: Augury text
0xF86 - 0xF9D: Ranking comments
0xF9E - 0xFBE: Augury advice
0xFBF - 0xFC2: Hannah quits!
0xFC3 & 0xFC4: Nils extra text
0xFC5 - 0xFCE: Prep. screen dialogue (it’d be nice if we knew how to edit the display)
0xFCF - 0xFED: Lyn’s mode ending sequence text
0xFEE - 0x1018: Class roll descriptions
0x1019 - 0x109E: Epilogue character endings
0x10C8 - 0x10E1: Unit command names
0x10E2 - 0x10E9: Map menu command names
0x10EA - 0x10F1: Misc. system text
0x10F2 - 0x1136: Stat screen text
0x1155 - 0x117A: FE6 chapter names
0x117B - 0x118B: Epilogue chapter roll text
0x118C - 0x11A0: FE6 data import
0x11A1 - 0x1224: Ranking screen comments
0x1225 - 0x12B2: Misc. system text (potentially debug menu?)
0x12B3 - 0x12BB: Mode select text
0x12BC - 0x12D2: Misc. system text
0x12D3 - 0x133D: Sound Room names