For the new test game, I think that Asoka starting with the shrine isn't a bad choice.
Toku is obviously in the game, and not paired with anyone.
Somebody starts with an extra settler, I think it would be almost too imbalanced if this were the shrine founder, but it is possible.
My thoughts on relating SPI, CRE and border pops weren't really consistent, but I'd suggest we have zero CRE civs, two SPI civs not including shrine founder, and six other civs. None of them are CHA.
I agree that there probably isn't any AI starting with Mysticism, else we could have lost the game already. But that doesn't say anything about the AI leaders, only their Civ. I'm not sure why Mali and Mongolia aren't possible.
Non CRE/CHA leaders remaining are:
Alexander, Genghi Khan, Montezuma, Ragnar, Shaka, Stalin, Bismarck, Isabella, Joao, Mao Z, Mehmed, Pacal, Peter, Darius, Elizabeth, Huayna C, Mansa, Justinian, Suleiman, Victoria, Wang K, Augustus C, Charlemagne, Qin Shi, Ramesses, Roosevelt, Frederick, Hammurabi, Sitting Bull and Saladin.
I think pick the religious zealots, generally aggressive and annoying to rush AIs. My list would be Asoka, Toku, Montezuma, Shaka, Isabella, Peter, Genghis Khan, Mansa Musa and Sitting Bull.