None of the Thieves Guild characters in Old Ebonheart offer training - this is unusual compared with Thieves Guild locations on Vvardenfell, where most guild affiliated characters offer training or a service
A large number of dungeon interiors that do not have the 'TR_' prefix in the name are missing NPCs or creatures. There seems to be a large overlap with the ones I found have path grid issues, reported here: https://www.tamriel-rebuilt.org/bugtracker/path-grid-issues-roth-roryn-i.... Listed here are the ones I found that I don't know are NPC'd in quest claims. In most cases, I don't know the intended use, so that needs to be looked up elsewhere.
This iron bucket with boiling water in Ebunammidan, Inner Shrine looks weird without the fire source to keep it heated. Otherwise, the interior is wonderful