Surely Padme is just that - the lotus flower?
Lucas probably didn't expect many Buddhists among his viewers!
And, I looked up
Anakin and was relieved to find this on BtN:
Lucas may have based it on the surname of his friend and fellow director
Ken Annakin.
I'd always suspected that he'd played with the spelling, and therefore the pronunciation, of an over-the-counter aspirin: Anacin in the US, but Anadin where I live.