My daughter had a different defect (she had gastroschisis) and was fed via Broviac IV and somehow I was supposed to get her interested in formula! I was referred to another mother who suggested that I feed her while watching kid music videos. I also distracted Natalie with something new/different each time (like I'd show her large beads or just anything around the house) to get her to look at something & she'd eat distractedly. This helped.
Also, our therapist thought she would benefit from therapy given to kids with sensory disorders (even though Nat did not have this prob), such as brushing her arms/legs with a soft brush slowly, then compressing her large joints (knees/elbows) gently, then ending up by rubbing my finger behind her front teeth. I think I did this 3x day. This really, really helped her eat 1/3 more!
After her IV was gone (and also her PEG tube after that), she still routinely hummed during meals, so I know the music was a plus.
We used a cup that had a section missing at the top, so it wouldn't be threatening. I didn't give her many bottles, just went straight to this cup, a special one our OT therapist gave us.
God bless!