We were only allowed to start on flute (screened) clarinet, trumpet and trombone - however they did experiement with saxophones my sixth grade year.
In 7th grade, we did a screening based on interest and features to move to other instruments.
Our orchestra teacher is considering only starting on violin this year and branching out in the second semester or next year. It's certainly not optimal, but I have concerns about kids signing up for band and not touching an instrument for so long.
No easy answers, for sure.