Minor as Pension Benefit Annuity Recipient

We have a 16 year old minor who is now receiving the remaining stream of pension benefits of her deceased father (the plan participant).  There is a custodian in place to make the payments to.  Just wondering about the minor beneficiary naming their own beneficiary of their benefit in case something happens to her.  Generally, it is my understanding that custodians do not have the authority to do that on behalf of the minor.  Anyone dealt with this before? 

Before one considers whether a conservator, guardian, custodian, agent, or other fiduciary has or lacks authority to act for the minor, one might consider whether the beneficiary has any power to name a beneficiary.

A retirement plan’s governing document might control and restrict rights to name a beneficiary.  Whatever right (if any) a participant has to name beneficiaries might end with the participant’s death.  Likewise, a contingent beneficiary might be the person the participant’s beneficiary designation named or, to the extent the participant’s designation is invalid, ineffective, or unstated, the person who or that results from following the plan’s governing document.