The correspondence with Luther was by letter. They didn’t like each other - they had completely different temperaments. The only Reformer as far as I know that Erasmus is on record as saying ‘I never disliked you’ was Martin Bucer - who was the most conciliatory of the Reformers and had a great influence on Cranmer’s second prayer book in the Reformed direction but not in a Calvinist one. but he didn’t approve of Bucer’s claim that he spoke with direct inspiration from the Holy Spirit. Erasmus only ever claimed to be a humble follower in the school of Christ who saw through a glass darkly. (
When this topic was first broached at EU there was some speculation that Bucer may have influenced the cancelling of the Anglican 42nd article about the necessity for believing in hell. But after much research I do not think this is so. Bucer was a moderate man in terms of the Reformers and was a tutor of Elizabeth’s first Archbishop the irenic Matthew Parker - but when he was Protestant magistrate Strasbourg he had had Hans Denck banished because of claims that Denck was a universalist (but he was charitable to Denck in saying that he thought him a fine man of good courage - and he didn’t have him killed). There was also speculation that Matthew Parker may have been behind the cancelation or abrogation of the 42nd article. However, although we do not have the minutes of Convocation, Parker’s annotations and deletions and proposed additions to Cranmer’s articles that he made beforehand as a basis for discussion and in his own hand do still exist. And the 42nd article is not crossed out in this. So whatever the reasons for its abrogation was, this happened in Convocation and/or was influenced by pressure from the Queen or her Ministers. There are lots of theories about this - but they can never be more than theories.
Regarding Erasmus and the OT - Erasmus believed that the OT was like a Platonic shadow of the New (using imagery from the Book of Hebrews’). And with the light of the New the clear day light of Christ has illumined and dispersed the shadows in the OT. So the OT must be interpreted in the light of the NT (as Origen also thought). I’m not sure what Erasmus made of the genocide texts but will find out for you some day soon I hope. Origen ceritainly consigned the genocide texts to allegory about spiritual struggle against vices - in his opinion they were not to be taken literally, Origen assigned four levels of meaning to scripture - literal/historical, moral, allegoric, and spiritual. Some assume that he thought all of scripture had all four levels of meaning - but this is not so (as his commentary on Joshua makes very clear). Some passages of stature, in his view, had all four levels of meaning but others had just one or two levels of meaning - especially those he found morally dubious in the daylight of Christ. Erasmus was enthusiastic about Origen’s fourfold level of interpretation - this much I do know.