I find your cordyceps gorilla more believable than your cordyceps lion. Both humans and gorillas distance related as they are both part of the ape family, while lions are felines. A disease jump to different species is very rare, but if two species are closely related to each other it is possilbe, look at bird disease it can easly jump for a pigeon to chicken, same with cow disease or pig disease.
Why not make Cordyceps Chimpanzee and Cordyceps Monkey? Humans are closely related to apes and monkeys and feel kind of kinship with them, and seeing something so closely related to humans infected is alot scarier and sends a message that humanity cannot escape this infection so easily.