The Splendona High School band is actually The Colony High School Band. The uniforms they are wearing are modified versions of the uniforms the band wore at that time.
The Texas "No Pass No Play" rule is enforced only at the end of each 6 week period, not at the moment the grade falls below passing. Starla would have been allowed the remainder of the 6 week period to get her grades up before being suspended from the cheerleading squad.
When Starla gets out of jail and is entering the lobby area, we hear someone answer the phone "Splendona Police Department". It is actually the Splendona Sheriff's Department.