Ok, so since Dustloop has seemed to have suffered a catastrophic meltdown, I'mma reiterate stuff that's happened in the last 24 hours;
Yesterday I went through every single 2-letter combo for all remaining categories and every [letter]0 and [letter]1 combo for non-weapon/emblem icons, ultimately unveiling 7 more icons (Clavis, George XIII, Hype Dog, Chrono Noel, Chrono Tsubaki, Lambda, and Relius' mask). Afterwards, Kurushii managed to use my Lambda code (n1) to find Lambda's emblem.
If you wish to still help, realize what's left will either involve the use of numbers, more than two characters, or both. Common code patterns noticed are xx, xxy, xy, and xx_x, with x's being letters and y's being numbers. All xx patterns have been tested, most likely xy patterns have been tested, and a few xxy patterns have been tested (mostly character codes + 2), but xx_x is largely un-routed. Bear in mind it's also possible that the codes may involve complete words like neta_seigi in the items icons.
So, as of now, the incomplete categories are
Items: 11/21
Sub Character: 21/25
Weapon: 21/22
Additionally, someone (sorry I did not catch your username) noted that they believe Jin's reference pallet to be Amaimon from Ao no Exorcist rather than Sothe. Amaimon fits the pallet better and furthermore, shares Jin's Japanese VA. For right now, I believe Amaimon to be a better fit than Sothe.