I think, if you have a blond wig and you can find a long, slim fitting white or pale blue dress (sleeveless or short sleeves -
maybe close-fitting long sleeves if they're semi-transparent) you'd be pretty much set for Lilliandil.
![Happy :)](./images/smilies/1.gif)
Caspian might be harder. I suspect finding a purple shirt wouldn't be too hard, but I think you'd want a Telmarine style coat or vest to complete the image. At any rate, something brown, almost knee length, and a high collar would be a plus.
Lastly, get pictures of the outfits you want to create the illusion of, and look at them when you're picking out your pieces.
![Happy :)](./images/smilies/1.gif)