It is better send the medical exam with the aos package, i helped a friend on june 2022.
we send the nedical exam with aos package, her case was completed in 2 months and she was lucky her interview was waived,
if you dont send the medical exam with aos package, you will get a rfe asking for it.
my friend also submit a vaccination waiver base on moral and religions convition and she was approved, she submitted form i-601.
about your child ask the doctor that waive the vaccination base in medical reasons a blanket waiver is call. In that case you dont need apply for a i-601.
on page 13 the doctor mark blank waiver