It's probably impossible to socialize a truly feral cat -- one that's fully grown and has never had contact with human beings. Kittens, however, are another matter. It sounds as if these little girls are happy to be in a loving home and will adjust very well.
Ditto the remarks about love, time, and patience. These kittens have been through so much. They were abandoned -- either by their mother or by some cruel-hearted person -- and they had to survive on their own, possibly during some severe weather. Then they were captured and moved to a shelter. Now, they have the added stresses of moving to your home and learning to live with people. But, they're lucky little girls, and I'm sure they'll become family members before very long.
Lori F. is owned by:
Sadie, the four-legged dog
Martin, the three-legged cat
Paul, the two-legged husband