In the intervening time since then, the little guy's siblings have been found, living in a small patch of woods not far from my house. One of them was caught and taken to a vet for shelter; the attempts to collect the rest of the strays continue.
However, today's piece of terrific news is that the caught one, "Oliver," has been adopted! He'll be going home with his new family in about a week. *happydance*
Thanks, universe! ^.^