No luck finding anyone who claims the kittens. A neighbor near where I found them told told me that the kittens were born outside and that the local kids (I found the kittens right in front of an elementary school) play with them, but that no one actually owns them. This would explain why they're so friendly! Most kittens born outside aren't as friendly as these (most aren't friendly at all!) In any case, this means I definitely need homes for these babies.
I've contacted local shelters and one has promised to take them as soon as they have space. In the meantime, I'll continue fostering and falling in love with the darlings more every day. If anyone wants a kitten, you know where to find me!
Update 11/15/14: A local shelter has taken the three kittens and promised to work hard to find them forever homes. It was hard to hand them over, but with a full house, I just couldn't keep them indefinitely, though I desperately wanted to! I miss the little darlings already.