J.C.
I would re-evaluate getting tubes & see chiropractor if they're because of ear infections. (Just an opinion) Also, I would see why she needs to be off of the bottle to have tubes in her ears, maybe it's because the sucking will "pop" her ears?
I haven't found the link between bottles & ear infections to be true for most babies, but you never know.
As far as the cup goes - at least she is drinking out of one. That's good! What about adding flavor to the milk and slowly lessening the amount you put in until she is drinking it straight (if she'll even drink the flavored) Otherwise keep introducing her to it & maybe lessen the amount of milk she gets by bottle so she might want the cup more. It's amazing how their little minds work!