Rolling inherited iBonds into 529

My mother passed away earlier this year, and had 5 iBonds with significant accrued interest. I was named as the Transfer on Death beneficiary on the iBonds, and I’m in the process of getting them re-registered in my name. I have 529 accounts for both of my daughters – currently age 14 and age 20 (in college and still noted as my dependent when filing). Assuming we meet the income parameters, am I able to take advantage of selling the iBonds and contributing to their 529’s to avoid taxation on the interest, or does that not work since I wasn’t the original purchaser? If I am eligible, do I need to hold the iBonds in my name for a certain period of time prior to liquidating? Thanks for any insights!