Moots fill the same social niche as the nuclear family. Childermoots are a special kind of moot, but moots can be formed without the intent to raise a litter. Biological factors limit childermoots to twelve members divided evenly between the sexes, but moots generally can have more members (though at least two people are required to form a moot), and moots don't need to have a particular gender ratio.
Childermoots cannot be embedded in a larger moot, as divisions and conflicts of interest can arise between parent and non parent members. However, the same looser associations that give rise to metamoots exist between childermoots and regular moots as they do between socially powerful and less powerful moots. Academic childermoots exist in this configuration.
Moots are considered legal persons similar to corporations on Earth. Assets such as land, bank accounts, property, etc. can be owned collectively by a moot, and moot members are usually contractually obligated to contribute some of their earnings to the moot as a whole.
Most yinrih societies do not recognize blood relationships beyond those between parent and child and among litter mates, though those relationships are quite strong. Involvement by “grandparents” in their “grand-pups'” lives is less prevalent, and usually indirect, with sires and dams interacting with their adult children who are now themselves parents.
More common is the involvement of unaffiliated siblings in the lives of the pups of their adult litter mates, as can be seen with Sherman's Aunt Breezy. And yes, the “sugar them up and send them home” strategy is just as common here as on Earth.
Child rearing can take different forms depending on the time and place. One method is to have all parents equally involved in taking care of the entire litter. This strategy can involve the entire family living communally as is usual on Earth, or individual parents can live singly, with each parent taking turns caring for a few pups at a time in rotation.
The other major strategy is for pups to be divided up among the childermoot early on, usually by the time the kits are weaned or by the time they start school, with one parent concentrating on the same smaller group of pups throughout their puppyhood. The other parents and their own young charges are treated like very involved aunts/uncles and cousins, respectively, by individual pups.
This second approach is employed by fostering orders raising human kids to more closely emulate the human family. Using Sherman and Doug from the Multiverse Inn as an example, Doug was responsible for closely monitoring Sherman's health and educational development, undertaking discipline for misbehavior, etc. Since the monks and their human fosters lived communally, the other monks were still heavily involved in Sherman's upbringing.
Speaking of religious communities, individual monasteries are legally considered moots.