The Book of Unwritten Tales 2

To make the disguise you need 'Small hat' found in the Zombie home where Zombie wife is. You also need a 'Feather' which is found by getting 'Socket wrench' next to the model world the robot built in Zombie home. Go to workshop and use Socket Wrench on 'Cuckcoo Clock' to get small bird and 'Feather'.
Get 'Cloak/ Cape' from the toy Knight that you find under the huge hole in the roof that you talk to Bill through. Combine all 3 items with Timmy? the little mouse (I think his name is.)

However the cook still knows you aren't Remi so have timmy distract her whilst you steal 'Tea towel' and wipe it on 'Dirty Dishes' outside of the kitchen. Replace it and ask for stew. Tell her it is to hot and she will wipe her glasses on the tea towel leaving her blind and then you can use the disguise on her to get the achievement.