Sorry that your daughter has had to undergo all those surgeries. Actually the fundoplication surgery is used quite routinely with babies and children who have reflux problems. As an open surgery, the Nissen Fundoplication has been around for about 50 years. It has been done laproscopically for a little over ten years or so. It's not usually an outpatient surgery (Maybe for children, I'm not sure), but most people only have to stay in the hospital overnight. If you'd like to see an animated video of the procedure, check out this link:
I had the surgery done on February 27th of this year. The recovery is quite easy--much better than I expected. The tests they usually do to determine the necessity of surgery are endoscopy, 24 hour PH monitor, barium swallow, and manometry. The manometry is the swallowing test. They use it to check and see if the swallowing reflex is normal and strong enough to withstand the resistance of a reconstructed valve (before surgery, with the weak sphincter (LES), it doesn't take much force to push the food through. This changes a bit after the surgery, so it's important to have a normal swallowing reflex. The manometry can also test the strength of the sphinter valve.
Manometry is the most challenging of the tests, since it has to be done awake, and requires a fairly good sized tube to be put through the nose and down the throat. You are periodically given a little water to hold under your tongue until given the signal to swallow. Most people find it a hard test to get through. I don't know how old your daughter is, and how well she tolerates tests. I didn't find it as horrible as some people do, but I know everyone is different.
I wish you lots of luck in your search to find answers to your daughter's problems. Please be sure to let us know what you find out. We're all here to give you as much support and information as possible, so be sure to ask any additional questions you may have.