Olivia is 18 months and I bought her a pillow ages ago and it is just another toy. We have tried sleeping with the pillowcases to get our scent on them but nope doesn't work. She just throws the pillow out of her cot. Mind you if she sleeps with us she kicks us off our pillows so who knows what she wants. I bought her one of the junior pillows from Big W.
Good luck trying to work it out. I'll be watching to see what others have done.