Can pork and mutton be marinated together?
Generally speaking, pork and lamb can be stewed together. The detailed analysis is as follows:

Pork and lamb can be cooked together in a braising liquid. Although their meat fibers differ, during the braising process their flavors can blend well. The rich aroma of pork can help neutralize the slight gaminess of lamb, while the robust flavor of lamb enhances the taste complexity of pork. Using spices such as star anise, cassia bark, and bay leaves to prepare the braising broth not only masks any undesirable odors from the meats but also brings out their natural savory flavors. When properly braised, both meats become tender, flavorful, and fully infused with the broth, without issues of off-flavors or clashing textures.
When purchasing pork and lamb, choose fresh cuts without unpleasant odors. Before braising, soak the meats in cold water to draw out blood, then blanch them to remove scum and impurities. During braising, control the heat carefully—bring to a boil over high heat, then reduce to low heat for slow simmering to prevent the meat from becoming tough. Once braised, allow the meats to cool, then seal and refrigerate them promptly. Consume within a short period to avoid prolonged exposure to air, which may promote bacterial growth.