For the requirement for risk free and hassle free account a CD or money market account through your local bank, credit union, or even large online bank will be fine. These funds won't grow very fast over time but they are safe and insured. These types of accounts are perfect for all the miscellaneous birthday, Holiday and religious event checks.
There is not a requirement that the money be in a UGMA (Uniform Gifts to Minors Act) account. Putting it in a UGMA account does make it hard for the parents to spend. The IRS does allow the child to have earnings from banks without the formality of a UGMA. The money shouldn't be moved between the parent's and child's account but it is possible for the parents to spend the child's money if times are tight and the money is used for items that benefit the child.
If there is a reasonable assumption of college then the 529 plan makes a lot of sense. The prepaid tuition options would be risky because they tend to be tied to a single state, and who knows where they will be living in 10 to 15 years.
The 529 does focus the money to be used for educational expenses, but it can be used for non-educational expenses if you are willing to pay the taxes and penalties. It can also be transferred to another child later, or even other family members. In my state the 529 plan doesn't have to be used right after high school graduation. It can be used up to 30 years after graduation. So they can decide a few years later that they want to go back to school.