Not much mention of the possibilities in Africa thus far. How about the Odinani religion practised in the safe-haven anti-slavery theocracy, the Kingdom of Nri? The ruler of their kingdom, the Eze-Nri, essentially filled the same role as the Pope in Roman Catholicism; and the big reason why the kingdom eventually came to an end in the early 20th century IOTL, after having endured for almost a millennia, was its strict adherence to a pacifist philosophy. In an ATL, you could have the Kingdom of Nri developing a less pacifist, possibly even 'saint-soldier' philosophy (continuing the Sikhism-analogue theme in the last few posts) during its peak (13th>17th century CE), waging holy crusades against the slave trade across much of West and Central Africa, and expanding its territory further in the process.
Depending on how soon this happens, and how successful their efforts are, the Atlantic slave trade could be weakened, crippled, or butterflied out of existence altogether. Several European ventures in the New World in the early Colonial Era would have been far less viable, and OTL's European colonial powers would have been less prosperous, diminishing their ability to impose their influence on the rest of the world. As a result, their missionaries would have had a harder time of it ITTL than IOTL trying to convert the people of Sub-Saharan Africa to Christianity, further boosting the chances of the 'Odinani-Nri' faith. What d'you think?