many items have no icon in inventory

This one is already fixed on the current build. The Horntail Necklace is item 1122000, and our icon lookup used to have no rule for the pendant id range — it fell through to "unknown", which meant no image address was worked out at all and the game never even tried to fetch one. That's why the slot stayed permanently empty rather than briefly blank. The fix went in on 7 August: pendants, belts, medals, earrings and eye accessories now correctly resolve to the Accessory folder, which is where v83 keeps them. I also confirmed the icon really is in the v83 character file and that the art server serves it. If you still see an empty slot after a fresh reload, please reopen this with a new screenshot and I'll dig further.