To what extent was purgatory replaced with alternative means of justifying the dead following the English Reformation?
There was no real attempt to replace Purgatory during the English Reformation. The Act of Supremacy, which separated the Anglican Church from Rome, contained no specific theological canons. Later, the Prayer Book of Edward VI established liturgy for the church; but again there was no mention of Purgatory. The Book of Common Prayer espoused the doctrine of salvation by faith alone. Since Purgatory was based on good works, this doctrine had no bearing on ones just deserts after death. The doctrine of Purgatory had been a strictly Catholic doctrine espoused by the church on the authority of the Pope. There was no scriptural reference to it. As the English church separated itself from the authority of the Pope, so it separated itself from the doctrine of Purgatory.
Elizabeth I did more than anyone else to placate English Catholics. She famously stated that she did not wish to establish "windows into men's souls," and therefore settled for outward conformity in religious matters. Only two sacraments were recognized, but sufficient Catholic practice maintained as to not offend the consciences of most Catholics.