"would allow future distributions from the non-deductible contributions to be non-taxable."

It creates a pro rata relationship. The "portion" rule is a Roth IRA rule, but it's more specifically stated as a Pro Rata rule for a Trad IRA.

Roth IRA allows you to contribute an amount (always after tax) and later you can remove the specific and exact amount or portion that was this basis contribution. It has ordering rules. It also has various 5-year rules.

Trad IRA has one big pot. That means any distribution later would result in a % computation, so that the % of basis (post-tax money) is used against the entire account value, then that % is applied to the distribution, and that results in the non-basis amount is taxable. That is why and how it avoids double-taxation.

There really isn't much impact when the parents fund the child's IRA. It's like asking if the child can sell stuffed animals to fund their IRA, and as long as they additionally have qualifying earned income, the money going into the IRA is just money.

I agree with everyone else: it should be Roth IRA, since there is no intent or need to benefit from a deduction.