Linda own's both Rosie's sire and dam. However, I am the cobreeder, and I was there for her dam's birth, shepherded her to her reproductive vet appointments, and I own Rosie's aunt and great uncle. I participate con several other basenji lists that were active long before this forum so that usually takes up all my free posting time. :p. I currently have a pack of four, including Rosie's brother Ra. My oldest dog Nut is not a basenji, but was adopted as a rescue and was a lonely 9 month old only dog until she was six months old and Rosie's great uncle Khonsu came home as a nine week old puppy. They got along beautifully, and still do. Three years later, Khonsu's niece and Rosie's aunt Jane camecto live with us. While she was still a puppy, she and Nut got along, but once she matured the household tension started. They have had several blood letting fights, and I'veclearned how to manage the household without running two packs, but it is NOT easy, and I cannot recommend it unless the people involved are completely dedicated to making it work. Where two or more boys can get along, often two bitches are not a good pairing; they can really hold a grudge. Breaking up a dog fight is no fun, and I've got the scars to prove it.
If Greg and Lisa want a companion for Rosie, I'm all for it when she gets to be 6 months to a year old. Then she will have bonded well with everyone in their family, and will be less likely to bond more with another dog than with the humans. She will be approaching adolescence, and they can do a better job of selecting a suitable lifetime companion for her and their family.