Hey Paula! When I first started, I made ready to ship items, but had the option of making each blanket or item custom or personalized. My shop has grown so that I do 100% custom work. I'd say to make different things as ready to ship items so that you have more listings so people can find you. I know you don't want inventory laying around the house, but if it helps your shop grow at first, why not take that step?
Another option is to make a separate listing for each size or color, just so customers can find you. Change up the title slightly just to see which keywords bring in the customers.
The Berry-licscous hat is adorable! You might want to rename it as a strawberry baby hat photo prop right in the listing, but still include Berry licious since it's a sort of 'branding'. One of my girlfriends is child photographer and 'photo prop' and 'newborn picture prop' are her most searched keywords.
Just something to think about!