14 months he got a toddler pillow and a blanket. He's obsessed
Around 1 for pillow and about 18-24 for duvet
We have baby duvet and he loves cuddling it. No pillow though as he just throws it out of the cot. He was 11 Months
I think you can introduce them from 12 months, but they don’t really understand the concept of staying under it to be warm until about 2-3 years old.
My LO sleeps on pillow and she is 10 months old she sleeps with a duvet as well never had a problem.