Singing is proselytizing?
I remember when my daughter was about 3 and we were in a drug store and she started singing Jesus Loves Me kind of loud. I was telling her to be quiet and a lady came up to me and said “oh, don’t stop her - that is so sweet”. I guess those days are long gone. We’d both probably be arrested now.
Hopefully not, but if the owner of the drug store doesn’t want any singing, you and your daughter do not have a right to do it as a Constitutional Right.
BTW, many of these restrictions as they apply to public spaces came about during the boom box era and the cacophony of audio assaults that were sent our way. Religious music enjoys no special protection when these restrictions are put in place. On the other hand, you can not single out religious express but allow rap and country music.