Smart home technologies are becoming increasingly common in households with children. While privacy and security concerns have been widely discussed, a critical issue often overlooked is the extensive data harvesting embedded in these smart homes and its manipulative impact on children through algorithmic decision-making. In this paper, we introduce FamiData Hub, a speculative prototype designed to empower families to navigate the datafication of smart homes. Through 17 study sessions—including speculative interviews followed by co-design activities—with 30 children and 25 parents, we found that families face challenges related to smart home datafication, such as the erosion of boundaries in family spaces, loss of control over family norms, and diminished autonomy in data-driven decision-making processes. Our findings offer key design recommendations for rethinking smart home technologies to better safeguard children’s data, advocating for respectful, family-centered approaches that challenge the normalization of datafication in domestic life.