Sorry to hear Mushu isn't well
. Hope he feels better soon.
I can imagine it's difficult getting him to take Baytril as I know both my guinea pigs detest the stuff and they're normally easy with meds (when they're ill).
The Applaws Chicken and Beef wet cat/kitten (I can't remember what it's called) Chicken and Beef is safe for hamsters, so you could buy a pouch of that. It's one of the best on the market, from what I can see (but I know nothing about cats lol).
Have you tried baby food? The Ella's Kitchen vegetable baby foods are mainly safe, but I will link a thread which has a huge range of recommended foods. Just double check to make sure they don't contain any lemon juice.
Baby food suggestions.