The anti-Ottoman alliance is OTL (and probably saved Ethiopia from Adalese conquest). Eventually the alliance broke apart and Ethiopia kicked out all the Jesuits.
Based on my earlier presumption, i decided to do some looking up on the church, and I can already see a flaw in spreading the religion, aside from all our PODs stated. None of us mentioned that until the late 1950s, the Ethiopian church was dictated by the Coptic Patriarch in Alexandria, who had always appointed a Coptic Egyptian as Archbishop of Ethiopia.
So creating a much earlier defined schism would go a long way to make Ethiopia more likely to prosetylse. First of all, a local Patriarch would probably be more concerned with all the heathens and heathen practices around, and could do a lot more to convince the emperor to deal with that problem, much more than a far away foreign patriarch would.
Secondly, if the Coptics had a similar policy to all clergy as they did for archbishops, then the Church may have had an alien element to it, or perhaps only appeared to the upper class. (Similar to Zoroastrianism in Sassanid Persia). Obviously this is mostly speculation due to Ethiopia being quite an obscure subject for most on the website.
However, the POD of a much earlier schism from Alexandria seems logical, hopefully with the Ethiopian Patriarch having large influence on Ethiopian emperors in terms of both internal and external spreading of the religion.