Made using info available here https://www.nexusmods.com/oblivionrem...
This guide, but with Unreal 5.3.2: https://github.com/AutumnFloof/HL-Mod...
Need to run console command "player.additem 0004DBF5 1" to get the KnightOfOrder armor and equip it when using this modding method. This method replaces the KnightOfOrder armor with a different mesh. This avatar mesh specifically is 1 mesh and 1 material, so only the armor's first material PNG files (T_KnightOfOrder_Helmet_D and T_KnightOfOrder_Helmet_NNRM) need to be replaced in addition to the mesh. Hard part is posing the avatar to align with the KnightOfOrder armor in Blender, clearing existing vertex groups, using the Data Transfer modifier to generate and transfer vertex groups data from the original armor mesh, and then merging and cleaning up the weight paints so the replacement mesh moves like-for-like.
Also might need to download the OblivionRemastered "usmap" file from Nexus Mods ( https://www.nexusmods.com/oblivionrem... ) for Model. Other than that, just follow the guides above to generate the FBX and PNG files in Unreal and assign them to a chunk so when built for Windows there is a .pak file matching the Unreal chunk number that was set to be renamed ending "_P.pak" in the game ~mods folder (OblivionRemastered\Content\Paks\~mods\yourfilename_P.pak). Settings needed in Unreal export to go smoothly are in the Hogwarts Legacy modding guide above.