As JoaD said, airway protection is one of the things they look for - which could be exactly what Zoe is doing when she coughs/chokes on food (as it is difficult to tell the difference between coughing and choking - some people go a little blue when coughing on food).

I cough on liquids a lot (food a little) when I'm due Botox (still cough on liquids sometimes even after), but my speech therapists have come to the conclusion that it's 'safe' coughing (even if it does go up my nose...) because I haven't come down with aspiration pneumonia (they did want to do two barium swallows, but the NHS said the usual 'not enough money').

At least the barium swallow/videofluouroscopy should give you some definitive answers re: texture/quantity/speed (as my g-tube is due to lack of quantity of liquid due to coughing on it).

The other thing is that if they feel any type of tube is needed, you should be able to discuss what type of tube with the doctor (in my younger children's hospital days, I knew a lot of kids with CF using NG-tubes who took them out each morning and their parents put them back in for over night).

They also might try different positions for swallowing as well as different textures - it really depends what they're looking for (as positioning can make a difference too).

Good luck,
Swift