Many religious buildings face uncertain futures, oscillating between preservation, underuse, and attempts at reinvention. Rather than beginning from existing adaptive-reuse cases, this contribution presents an action-research program that prototypes new forms of community-rooted, commons-oriented activity within ecclesial infrastructures to study the conditions under which they can flourish. Drawing on P2P/commons theory and grounded in the Church's "ecological turn," the project treats these spaces as latent "convivial infrastructures" where peer-to-peer relationality, mutual care, and cosmo-local practices can be intentionally seeded and iteratively refined. From this perspective, adaptive reuse becomes a pastoral expression of ecological stewardship: enabling sacred spaces to support sustainable, cooperative, and inclusion-enhancing forms of communality. The core research question is not how religious buildings have been reused, but how they can become generative nodes of a commons-based social economy-provided enabling conditions, institutional support, and appropriate governance patterns are in place. The program seeks to identify leverage points for scalability, trans-local learning, and pastoral compatibility. Prototypes act as "living laboratories" where hybrid civic, ecological, pastoral, and cultural functions co-evolve, revealing both successes and the tensions inherent in transforming religious infrastructures. In this light, adaptive reuse becomes less a matter of functional adjustment than of cultivating new social grammars within inherited sacred settings. Such prototyping, we argue, illuminates how religious infrastructures might contribute to broader transitions toward distributed stewardship, solidarity-based economies, and renewed forms of belonging, caring, and worship-while making visible the gains, losses, and negotiations that accompany any attempt to reinhabit tradition toward emerging futures.