Have you washed the duvet with an enzymatic cleaner so there's no residual odor? If your washer isn't large enough or you don't have a dryer, most laundromats have industrial-sized machines. Put a tennis ball in the dryer to fluff the duvet. I usually hang our king-sized down duvet up for a day before putting it through the dryer.
I'd also get rid of the litterpan liners. A lot of cats don't like the feel or plastic smell of them. They're also less hygienic than doing without because urine seeps through small tears caused by the cat scratching the litter and collects under the liner, making the cat smell a "dirty" box no matter how many times a day you scoop.
Kittens are a lot of work, but the messy hyperactive phase passes all too quickly.
I'd also get rid of the litterpan liners. A lot of cats don't like the feel or plastic smell of them. They're also less hygienic than doing without because urine seeps through small tears caused by the cat scratching the litter and collects under the liner, making the cat smell a "dirty" box no matter how many times a day you scoop.
Kittens are a lot of work, but the messy hyperactive phase passes all too quickly.
