So, Anglican theologians like John Keble and John Henry Newman (who later converted to Roman Catholicism) built off of a notion advanced by the 16th Century Anglican Divines that viewed Anglican Christianity as a distinct branch that developed alongside Roman Catholicism and Orthodoxy. Things like the Synod of Whitby are cited as evidence that the Roman church worked hard to bring this distinct form of the church inline with Roman polity and practices (in some views Celtic Christianity is viewed as being part of this wider “English” branch of the faith). This resulted in a long-standing tenuous relationship with English Christianity and the Catholicism of continental Europe (reflected in things like the Sarum rite, etc.). So when the Reformation happened, this gave the opportunity for English Christianity to pick up where they left off and live into that distinct mode of being.

Given this, according to branch theory proponents, there would be Anglicans in the 900s. They were just put under the veil of Roman Christianity at the time.

If you don't eat the brain you'll have a much much lower risk (your link suggests about 9x less likely), and if the person you eat wasn't a cannibal then your risk is lower still.

Also worth mentioning that Kuru is a specific disease for natives in Papua new guinea , and it only existed for about 100years and was going away on it's own when the cannibalistic practice was outlawed.

I think the health risks of cannibalism is very exaggerated.

(this is not an endorsement of cannibalism)

Kuru is just one form of prion disease that was found in one group of people. And from what I remember, it has never been found elsewhere, as it most likely developed as a sub-type of Creutzfeldt-Jakob disease(another prion disease)