Layer isn't ideal for Cookie, flock raiser or grower would be better for his health. Yes he will grow spurs, you can clip the very tip off so they aren't sharp and won't hinder him or hurt the hens. I use a set of cat/dog nail clippers and only clip 1/4 inch to 1/2 inch depending on growth. If...
I think if you explain the situation they will be suprisingly understanding, most folks don't want to upset a child. And besides Cookie is a rooster-lite, he won't be super loud and his danger factor is next to nothing not to mention he's cute.:)