When I did the model-swapping for my Tale of Two Towns mod, it really just came down to brute forcing it for the player models because there weren't any appropriate tools. I figured out which file had the player models (turns out they were all in people_pal_data.bin) and then went line by line...
Were you able to actually successfully open the .bum files with Noesis? I can't find a working plugin anywhere. (Chrrox seems to have removed theirs from xentax, but seeing as that was made for another studio's game, I'm not confident it would have been useful for this anyway).