You will need to take him to the vet first and hopefully neuter. He needs a fecal done to ensure he does not have parasites he c an give your girl. Then a 30 day quarantine. After the quarantine, another vet visit and fecal and if all is good, you can begin scent swapping. You shouldn't just stick them together because one may be sick and get the other sick. What diet are you planning on feeding? As far as meats go, it depends pretty much on what diet you are feeding. If OHPW, you on't need a protein. And protein should be boiled or baked chicken without any season, scrambled eggs (no cooking oils or seasonings) and you can use ground turkey as well. Just never season any of their food. Or you could be safe and feed yogurt. With no artificial sweeteners.