There is no need to ‘appeal’ anything. Federal judges have absolutely zero jurisdiction over states and localities in matters of religion. The 1st Amendment refers only to “Congress”, and the 10th Amendment reserves all powers not limited by the Constitution, to the states, and the people. The school need only announce they are nullifying the ruling, and remove the covering over the banner.
The lawyers get $173,000. The girl gets $25. Not quite 30 silver pieces. But she WILL be remembered forever for this. Enjoy being the town bleephole.