I love this story! I've actually read up to chapter seven and am waiting patiently--or rather, attempting to wait patiently,--for the next chapter! You have yet to tell us which animals Marly and Larxene are!
Demyx as a rabbit...it fits! Saix as a wolf is also fitting, seeing as he's the Luna Diviner.
Please update as soon as you can! This is an excellent story!