EDIT: And after all that... transparency doesn't seem to work correctly with animated textures.
The Art is a fickle creature

After 5 hours of some shut-eye, a new object and D'Lanor's suggestion of deleting the Age's .sav file and everything seems to be animating just perfectly. I haven't done a single thing differently, so I'll have to assume that deleting the .sav file is probably the key component to success. Worth bearing in mind in future... thanks!
-: D'eux :-