Bcres files are not cross compatable from one game to another, the models inside specifically. So pulling the model and textures out and moving them into NewLeaf won't work.
I havent had any luck with any custom made bcres files of any kind yet. I think only mega-mew has had suvh luck and they don't seem to be currently involved with animal crossing havking at the moment.
appearently, custom models requires having a specific PC setup, the ctr dev kit, a 3D program that works with the dev kit (maya I think) and much more knowhow than I have for sure. I can't figure out how to set up a clean dev environment without screwing something up or expiring a free trial on something or another, so I think I'm stuck where you might be stuck
Good luck nonetheless, I think it would be really cool to have a lightsabre ax!