SilverLit City - All Feathers, Chests, Codex Exploration Guide (No Edits).

LO (means it requires logout method.)
0:12 Feather 1 - LO
1:44 Feather 2 - LO
2:22 Feather 3 - LO
3:25 Golden Key (Buy Honey)
3:39 - 4:09 Memorial Key
4:24 Feather 4
4:35 Wishing Key
4:55 Golden Key (Buy SilverLit candy)
5:05 - 8:10 Key (Kill Lizard and turn in Precision Gear for Gaia Key)
5:15 Feather 5
5:57 - 6:01 Chest - Memorial Key
6:39 Golden Key (Buy Doll)
6:59 Golden Key (Buy Map Piece)
7:05 Feather 6
7:24 Feather 7
7:39 Feather 8
8:03 Golden Key (Buy from Izzy)
8:32 - 8:39 Cattelan II's Key
9:05 - 9:15 Catherine's Key
11:54 Fabre's Key (From Library of Chaos dungeon by first boss)
12:26 - 12:36 Chest - Wes Kuan (Wishing Key)
12:48 - 12:53 Chest - Catherine
13:00 Chest - Gaia
13:18 Chest - Cattelan II
13:28 Feather 9
13:58 - 14:03 Chest - Golden
14:30 - 14:40 Chest - Fabre
15:50 - 16:39 Orrin's Key
17:05 - 17:10 Chest - Orrin
17:20 - 17:26 Feather 10
17:35 - 17:47 Feather 11
18:05 Feather 12
18:20 Codex 1
18:35 - 18:55 Feather 13
19:22 Codex 2
19:30 Codex 3
20:21 - 21:48 Gamma's Key (Waterproof Silver Letterbox grants quest)
22:42 Chest - Gamma
Not Shown, but Fishey Boyle chest key is found by fishing in SilverLit City.

[@Mantampah]

Much appreciated 😄