De-ageing Natalie Portman is a really cool idea. It might look a bit weird later in the movie though, when she’s not covered by robes and her limbs clearly have an adult’s proportions.
I was waiting for someone to mention this! There are limits to what can be done but for edit purposes I still think mileage can be found in a 3-in-1 or even an abridged TPM that cuts down a lot on Padme, she still has a good amount of close ups to piece together something convincing with clever cutting, though I would need to check again to see how much leeway is really there.