Okay, I think I found the out the reason for the Double Entries in ESM..
Some of the Ren hair textures have a fixed textures path aka pointed to use programs files/bethesada softworks/oblivion/data/textures those are the ones with f.nif..
those with fnd.nif are fixed to use absolute paths instead . data\textures\ etc..
You said you packed everything into BSA so it maybe this causing them to act that like in menu ?
Try usng TES4FILES to correct textures path and then repack the bsa afterwords..
Corepc
alot of them rens hairs have fixed textures path looks like they where just never removed from the Cobl.esm itself and let playable in the Cobl Races.esp..